another 496bbc

Discussion in 'Engine Combos and Dynometer Database' started by grumpyvette, Jul 12, 2011.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    this thread will contain several totally different engine builds with parts listed and when available the dyno results from the engines built,
    it will be used as a guide to allow readers to compare the basic engine components , at least a bit too get a good idea as to the components selected and the expected results.
    first thing Im forced to point out is theres several completely different 496 BBC engine build links, contained in this and linked related threads...
    most are not designed as racing engine, those would have 12.5:1-13.7:1 compression, almost always a hydraulic or solid roller cam
    and perhaps a tunnel ram intake or stack injection, maybe even super charged, etc.
    featuring parts lists and dyno results in this thread,
    can be rather useful for comparing potential build ideas.
    next the whole original concept was to point out the differences in the builds and results not to say any one particular build was a prime example of what to build.
    I started out with the build having the 265cc oval ports as a reasonable mid power range as a base line , not as the ideal build,
    I also wanted you and anyone reading through the linked info to see how increases in port size compression and cam duration in similar displacement
    (496 CID in most cases) engines tended to cause different power curves.
    500hp-600 hp will be rather common,
    personally Ive found the 280cc-300cc oval port heads and the 305cc-315cc rectangle port heads on the BBC engines to be about ideal,
    PROVIDED the compression and cam timing choices are carefully matched to maximize the head ports flow potential.
    generally if your going to build a hotter street performance engine for a daily transportation used with commonly available pump octane gas,
    perhaps an auto trans with a 2700 stall converter and 3.36-3.73:1 rear gears , and a decent dual plane intake,in what is basically fast daily transportation, in an older muscle car,
    you want a 9:1-9.5:1 compression, a set of 280 cc-290 cc oval port heads and a cam duration in the 235-245 @.050 lift range and lift in the .580-.630 range flat tappet or hydraulic roller.
    if you want increased performance and are willing to sacrifice some drive ability,
    you might want to select a bit more compression, IE 10.0-10.5:1
    the smaller rectangle port 300cc-315cc heads , a single plane intake , 3.73:1-4.11:1 rear gears
    at least a 3000 rpm stall converter and a cam with about a 245-250 duration @.050 lift range, and lift in the .610-.715 range, almost always a hydraulic or solid roller, 600 hp-700 hp or a bit more is available.
    assuming the proper headers exhaust and carb sizes are selected the difference in power could easily be 60-120 hp or more difference
    between the two basic concepts and obviously a loss in easy street driveability in bumper to bumper traffic, you simply,
    e make choices based on what your willing to put up with and what you want to trade off in drive-ability to gain performance.
    before you buy components talk to both the vendors and your machine shop of choice , you damn sure don,t want mis-matched components and clearances.
    you need to measure accurately, know what your current block will function correctly with and pay attention to clearances and other details that make or break the engines potential durability and power potential.

    blueprint engine blocks


    world products blocks

    G.M. performance
    496 Gen V BBC
    AFR 265cc Ovals CNC chambers
    Eddy RPM AirGap w/ 1" spacer
    850 AED HO carb (80 primaries / 88 secondaries)
    10.7:1 compression
    Morel hyd rollers
    your cam...250/258@0.50...660/.612...108 LSA in at 103 ... ine-block/

    It put up 655hp @6300 and 639tq @4600

    32 total on timing

    3400 549.0 355.4
    3500 562.5 374.8
    3600 589.6 404.2
    3700 595.4 419.5
    3800 597.6 432.3
    3900 600.8 446.2
    4000 605.3 461.0
    4100 611.1 477.0
    4200 619.4 495.3
    4300 628.5 514.6
    4400 633.6 530.8
    4500 636.2 545.1
    4600 639.3 559.9
    4700 636.5 569.6
    4800 634.0 579.5
    4900 631.3 589.0
    5000 624.2 594.3
    5100 622.6 604.6
    5200 613.3 607.2
    5300 614.0 619.6
    5400 608.2 625.3
    5500 599.6 627.9
    5600 596.5 636.0
    5700 593.5 644.1
    5800 583.7 644.6
    5900 574.7 645.6
    6000 571.8 653.3
    6100 559.4 649.7
    6200 549.4 648.6
    6300 546.3 655.3
    6400 537.4 654.9
    6500 526.1 651.1
    6600 512.2 643.6
    Last edited by a moderator: Feb 16, 2019 at 3:26 PM
  2. grumpyvette

    grumpyvette Administrator Staff Member


    rectangle port heads generally work best on 500 or larger displacement engines
    with at least 10:1 compression and cams with at least 245 duration at .050 lift and valve lifts over .600 to take advantage of the potential port flow rates

    (take advantage of millions of hours of previous engine builds, by skilled and experienced people, and the knowledge gained)
    A couple days of
    reading the linked and sub-linked info

    could save you a great deal of wasted time and money
    and money spent on wrong or un-necessary parts
    read the links and sub links below

    a day or so spent doing reading and research,
    (reading links and threads)

    will frequently save you thousands of dollars and weeks of wasted work.
    if you want a fast dependable car you will need to either do the research required to know exactly how and why things should work, or pay someone else to do the work that has taken that time and effort.

    @ ... ock-build/ ... big-block/ ... /A-P1.html ... /A-P1.html ... ine-build/ ... /A-P2.html ... ock-build/ ... old-block/ ... nder-2000/ ... der_heads/

    a hydraulic roller cam similar to this in a 10:1-10.5:1 compresion BBC engine with a good dual plane intake, and long tube headers with a low restriction exhaust, a manual transmission and a 3.71:1-4.11:1 rear gear., will wake up many BBC combos designed for street / strip use

    here is a direct quote off a different site from a guy that just had an engine built by Mark Jones @
    "Hey guys, here are the details of the 496 BBC I just had build.

    496 4 Bolt Main,
    10.2 comp,
    Mahle custom modified dome pistons,
    .238 @ .050 hyd roller,
    AFR 265 heads,
    RPM air gap intake."



    having a good high capacity baffled oil pan on your engine adds considerably to its potential durability and potential life span


    I frequently get questions on the subject of selecting the correct heads and cam for an application, well its not as difficult as some make the process out to be and theres guide lines and calculators you can use to narrow the selection, so lets go thru selecting a set of heads fora 496 big block engine so you can see how things get narrowed down.
    theres obviously good and bad choices and some choices will obviously be better matched but NONE will be perfect theres always compromises to be made, simply because you don,t run an engine at a constant rpm under a constant load at a constant enviroment or temperature.
    the usual goal is to maximize the torque curve over the most used rpm band, with a reasonable race track potential
    obviously youll need to know the engine displacement compression ratio and its intended use and keep in mind that your NEVER going to find the PERFECT HEAD for all factors but you usually can come amazingly close if you just give up on trying to make the heads you can get the best price on try to fit the application and concentrate on selecting what you need and then finding the cylinder head thats a good compromise

    IF it was my camaro ID use an edelbrock 7561 air gap intake and a holley 850 cfm carb, it would sacrifice a bit of peak horsepower but more than compensate in extra mid rpm torque

    ......................Piston Alloy Comparison
    ...................................................... 2618
    High silicon............................................No silicon
    Low expansion........................................expansion
    Tighter piston-to-wall clearance................More Piston-to-wall clearance needed
    Quiet Operation......................................Noise when cold
    Less ductile............................................More ductile
    More stable & consistent.........................Higher resistance to detonation
    Longer life cycles....................................Shorter life cycles
    Harder...................................................Softer ... 7ibJ7FwU4M ... wordSearch



    calculators ... ock_build/ ... _build_up/ ... ock_build/


    OK FIRST example lets build a 496 big block designed to be a camaro /muscle car engine with a manual trans and a 3.73:1 rear gear thats a week end toy,and daily driver that runs on pump gas but still makes decent power.
    KEEP IN MIND THE GOAL IS NOT PEAK POWER but a good compromise where good mid range torque instant responsiveness and impressive power levels in a semi-streetable combo make for impressive street performance

    looking at the charts and doing some basic calculations we find that max piston speed should most likely be kept to about 4250 fps to provide durability and thats about 6000rpm with the 4.25" stroke on a 496, we will try to keep the quench at about .040-.044 and the dynamic compression near 8:1 ,averaging the calculator results we find that port cross section can be a minimum of 3.2 sq inches and a max near 4 sq inches,if we don,t want to have port stall or low port velocities, so lets pick about 3.6 sq inches as a compromise, middle ground. if we use a 2.3" intake valve on that 496 we have 62 cubic inches per cylinder and find the calculators say we need a tight 107-108 lsa, (we might want a slightly wider LSA to get the idle a bit smoother, and big block rollers with tighter than 106 LSA are hard to find) and a .680-.690 valve lift to maximize port fill efficiency, with a .50 mach port speed
    looking at the charts we see the duration of the cam will most likely fall in the 245-260 duration @ .050 lift range, for a street cars engine to maintain max mid rpm torque.
    so at that point we know we need a cam and head port and combustion chamber and compression combo that matches that range, we can find a wide range of piston dome or dish sizes so lets look at head flow also, youll want about a 20cc-25cc dome piston to get the 10.5:1 compression and correct static and dynamic compression, obviously things like head gasket and combustion chamber and dome must be tweaked during calculation to find the ideal combo as components selected effect results

    TRICKFLOW 280cc ... %20280.pdf ... toview=sku

    PROFILER 290cc

    HERE, above youll see A couple GOOD CHOICEs IN THIS CASE, as they flow 340cfm with mild clean-up at that .680 valve lift

    heres the roller cam Id select for that application

    heres DD2000 wild guess at potential results of that combo

    related threads and links with a huge amount of related info you need to know







    related build info

    if your thinking of building a big block chevy, keep in mind theres two common block deck heights the standard pass car 9.8" and the taller truck block with its 10.2" deck would help, but if its a tall deck block theres adapter plates
    are used on a standard intake because of the greater distance between the gasket surfaces on the tall 10.2" tall deck block vs the standard 9.8" deck height, if the adapter plates look like these its a TALL TRUCK BLOCK, 427 based engine

    why would anybody want to use adapter plates, if there are so many correct intakes available?

    look here for tall deck intakes that should work ... take&dds=1


    There are gaskets made specifically for this swap. Use other gaskets at you're own risk- these are what you want (from a V/R press release, presumably prior to the Gen 6 engine release):

    General Motors 7.4L Head Gasket
    General Motors (GM) 7.4L (454 CID) engines use two types of engine blocks: the Mark IV and Mark V. The Mark IV is found on 7.4L engines in model years from 1965 to 1990, and the Mark V is found on 7.4L engines in model years from 1991 and newer.

    Often, installers will attempt to adapt a Mark IVcylinder head for a Mark V block. This conversion can be made if attention is paid to the coolant circulation. Mark IV and Mark V have different coolant flows and were originally designed for different head gaskets. If the conversion is not performed correctly, the engine will overheat, causing premature engine wear and damage.

    Victor Reinz has designed two Nitroseal® head gaskets to specifically allow for this conversion. The installation requires Victor Reinz part number 4918 be installed on the right cylinder bank to maintain proper coolant circulation, and part number 4923 to be installed on the left cylinder bank for the correct coolant flow.

    Victor Reinz part numbers 4918(right bank) and 4923 (left bank) are available for GM 7.4L (454 CID)

    well its because the adapter plates allow you to use a standard intake on a tall deck block and the adapter plates are significantly less expensive than a tall deck intake which can ONLY be used on the tall deck block applications while the standard intake and adapter plate combo allows the intake to be used on either application


    You tell the bare blocks apart by looking at the distance above the top water pump bolts to the block deck surface!
    look very closely at the distance between the upper water-pump bolt holes, the standard block on the left is noticeably closer that the tall deck on the right
    Shown on the diagram: 10.75" vs. 11.03" = .28" taller block china wall on the lifter gallery
    thats true for the block china wall but not the intake

    your forgetting the wider distance between the heads requires spacer plates and four intake gaskets, and end spacer plates each about 0.125" thick that raised the intake

    trust me the intakes carb mount surface with the same intake used on a tall deck block sits about 5/8" higher on a tall deck application
    read these links






    Tall deck blocks bolts are 3/4" from the bolt holes to the block decks while the more common pass blocks or standard deck blocks are about 3/8" from the upper water pump bolt holes from the block decks.

    standard intake on tall deck block showing why spacers are required



    crank ~$800


    mark iv blocks
    mark v blocks
    (keep in mind that ALL '91 and later Gen.V and Gen.VI big blocks come with 4-bolt main caps. The two-bolt big blocks are no longer in production
    MANY BUT NOT ALL aftermarket head designs have been modified to work on both the early MARK IV 1965-90 and later MARK V & VI blocks 1991-later.)

    BTW, , on BIG BLOCKS the oil pumps and oil filter adapters are different due to the block oil filter recess and rear seals being different
    GEN 4 or MARK IV

    GEN V and VI

    standard block is clearanced for 8.5"
    truck block for slightly wider 8 5/8"

    stroker cranks will frequently require the lower cylinder edges and outer block rails be clearanced ground to clear rod bolts and rods, but be very careful as the lower block casting is thin in some places



    the first few rule's of GRUMPY'S engine assembly





    (2) if in doubt, about how to do anything, on an engine, do some detailed research,
    find and compare at least 3-5 valid trust worthy sources info,
    read the instructions over again, several time's very carefully
    and if available watch several related videos.

    (3) if any component will not easily function as designed or requires a good bit of physical force to install ,
    or your not 100% sure your doing something CORRECTLY

    theres a reason, and you better verify your clearances are correct , and your following the instructions before you proceed.

    (4) never assume the parts you purchased can be used without carefully , cleaning them prior too,
    checking the physical condition, verifying clearances and using the correct sealant, lubricants etc.

    (5) the quality of a component is generally at least loosely related to the cost to produce it,
    and the amount of detailed research and quality machine work that went into its production.
    if you got a significant reduced price, theres typically a reason.
    it might simply be because a new improved part superseded the one you purchased,
    but it might be a far lower quality imported clone with lower quality materials and machine work.
    its the purchasers responsibility to research quality.

    (6) if you did not do the work personally or at least take the effort to verify it was done correctly and personally verify clearances

    ITS almost a sure thing that it was NOT done , correctly, and yes that mandates you fully understand what your looking at,
    and how the components are supposed to function and have high quality precision measuring tools.


    ID suggest you select from heads from these sources
    Jegs; 800/345-4545;

    Summit Racing; 800/230-3030;

    Scoggin-Dickey Parts Center; 800/456-0211;

    TRICKFLOW ... 4294867081
    1-330-630-1555 • 1-888-841-6556


    Dart Machinery; 248/362-1188;

    toll free: 877-892-8844
    tel: 661-257-8124

    Patriot Performance
    Patriot Performance; 888/462-8276;

    Toll Free: 877-776-4323
    Local: 901-259-1134

    EDELBROCK ... main.shtml
    Edelbrock; 310/781-2222;

    BMP (world products)
    Tel: 631-737-0372
    Fax: 631-737-0467






    this would be a great time to carefully read the links below. :D
    a properly set up fuel delivery, system, fuel pump and filter,
    and tuned carb goes a long way toward making the car both perform and dependable.

    understanding how everything should work,
    and whats required,in a properly set-up fuel delivery system, knowing how too select and design and install, and correctly match components,
    will go a long way toward making the performance car application run better than you might imagine.




    a couple known dependable engine builders
    Last edited by a moderator: Nov 8, 2018
  3. Indycars

    Indycars Administrator Staff Member

    Surely I can't be reading this right....Grumpy you HAD and engine built ???

    Very nice numbers, the HP just keeps climbing until the table stops at 6300 RPM ! What's involved in buying custom pistons ??
    Last edited by a moderator: Feb 17, 2016
  4. grumpyvette

    grumpyvette Administrator Staff Member


    SORRY I should have made that post source clearer,
    no thats a direct quote off a different site from a guy that just had an engine built.
    I copy and pasted it to show you gentlemen the results of a valid combo and how it doesn,t take a huge cam and extreme compression to make decent hp, it takes matched components and a great cam, heads and decent compression

    yes I,m only too well aware most of those reading the thread will never bother to read the links and sub-links but its your lost opportunity, to learn a great deal if you do ignore the linked info


    [​IMG] ... ewall.html ... lator.html









    viewtopic.php?f=87&t=4788&p=13003&hilit=calculators#p13003 ... torque.htm

    POWER (the rate of doing WORK) is dependent on TORQUE and RPM.
    TORQUE and RPM are the MEASURED quantities of engine output.
    POWER is CALCULATED from torque and RPM, by the following equation:

    HP = Torque x RPM ÷ 5252
    Figure 3

    Note that, with a torque peak of 587 lb-ft at 3000 RPM, the pink power line peaks at about 375 HP between 3500 and 3750 RPM. With the same torque curve moved to the right by 1500 RPM (black, 587 lb-ft torque peak at 4500 RPM), the peak power jumps to about 535 HP at 5000 RPM. Again, moving the same torque curve to the right another 1500 RPM (blue, 587 lb-ft torque peak at 6000 RPM) causes the power to peak at about 696 HP at 6500 RPM

    Using the black curves as an example, note that the engine produces 500 HP at both 4500 and 5400 RPM, which means the engine can do the same amount of work per unit time (power) at 4500 as it can at 5400. HOWEVER, it will burn less fuel to produce 450 HP at 4500 RPM than at 5400 RPM, because the parasitic power losses (power consumed to turn the crankshaft, reciprocating components, valvetrain) increases as the square of the crankshaft speed.

    The RPM band within which the engine produces its peak torque is limited. You can tailor an engine to have a high peak torque with a very narrow band, or a lower peak torque value over a wider band. Those characteristics are usually dictated by the parameters of the application for which the engine is intended.

    An example of that is shown in Figure 4 below. It is the same as the graph in Figure 3 (above), EXCEPT, the blue torque curve has been altered (as shown by the green line) so that it doesn't drop off as quickly. Note how that causes the green power line to increase well beyond the torque peak. That sort of a change to the torque curve can be achieved by altering various key components, including (but not limited to) cam lobe profiles, cam lobe separation, intake and/or exhaust runner length, intake and/or exhaust runner cross section. Alterations intended to broaden the torque peak will inevitable reduce the peak torque value, but the desirability of a given change is determined by the application.
    if you don,t think use of the correct valve springs and rockers matters heres the dyno results on a 496 BBC chevy engine with a new set of valve springs and roller rockers, obviously if correctly selected,they can make a difference

    are you guys aware that AIR FLOW RESEARCH maintains a list of articles to engine builds ?
    even if you don,t do more than read thru and take a few notes there's a good deal of interesting info posted
    [​IMG] ... /A-P1.html ... /A-P1.html ... /A-P1.html

    you tend to have to watch a couple dozen guys assemble engines and, do it while you pay real attention, and/ or
    watch several dozen similar videos to get that perspective and pick up the little differences and omissions in how each guy approaches and completes the process.
    yes youll undoubtedly see some guys skip over or ignore things that other guys feel are critical, but if you pay attention and really think things through and stop and ask your self
    (why is that guy bothering to take the time to bevel that bearing edge)
    (why is that guy verifying the oil pump stud does NOT touch the rear main cap bearing shell)
    , or
    (what the hell is a thrust bearing?)
    (what was the oil pump drive shaft to distributor gear clearance?)
    (what were those rod and main bearing clearances?)
    (how did he verify the piston to bore clearance?)
    (how do you verify rod bolt clamp or stretch?)
    (how do you get the damn damper on)
    (what the hell is quench)
    (compression height?)
    (maximizing ring seal to bore)
    (what do you mean don,t beat on that damper?)

    engine assembly is mostly the hard logical application of physical science with a bit of intuition, where the engine assembly technician and engineering testing is used to verify exactly what is and what is not functioning as its intended too.
    the fact is that the engineers and computer simulations can get things about 80% -to-85% to being as close to ideal, but the fact is the guys that control production costs and emission controls will always have some input and the production engineers will make cost reducing changes in the designs, the individual engine builder will get their hands on the O.E.M., engines and find ways to TWEAK, the as delivered engines to produce even better results, then the aftermarket will take a long hard look and start figuring out ways that they could further boost power with less concern for cost and emissions and a bit more concern for power output, then the engine builders will take those parts and TWEAK those parts and the cycle will continue several times until the original engines design has markedly been improved.
    theres always a big factor in the selection of engine components ,
    for most of us and thats obviously the COST VS potential power gained.
    what many guys fail to look at is the valve lift vs flow numbers, and intended application,
    I does you darn little good to purchase a killer BBC, set of 360 cfm rectangular port cylinder heads that flow 400- 450 cfm at .800 lift if ,
    your cam selected max's out a .650 lift, its not designed to maintain valve control at over 6000 rpm, and your intake port flow stalls at 390 cfm
    especially on something like a 9:1 compression 454 BBC, with a typical 750 quadrajet carburetor on a Stock style low rise dual plane intake,
    yet I see similar mis-matched components rather frequently , usually from guys that got KILLER DEALS on lightly used race engine parts they picked up at bargain prices at swap meets.
    look over the parts your selecting very carefully and use some logic in matching components, if you realistically won,t be running the engine over 6000 rpm, and your displacement is under 427-454 cid, your very unlikely to benefit

    lets do some MATH
    lets assume you want to build a kick ass 540 BBC

    a 540 has a 4.25" stroke and 5200 f.p.m. in piston speed would be a reasonable upper rpm limit (7350 RPM )if you intend to maintain reasonable long term durability.
    now that would MANDATE a solid lifter cam (ideally a roller solid lifter) valve train to maintain valve train stability in most cases.
    at 7350 rpm a 540 will in theory use 1723 cubic feet of air PER MINUTE
    thats 215.4 cubic feet of air per minute per cylinder
    67.5 cubic inches per cylinder x 3675 intake strokes,
    thats about 1723 cubic feet of air per port, per minute, and 3675 intake strokes per minute
    thats .469 cubic feet per intake stroke ,
    (theres 144 cubic inches in a cubic foot) and a cylinder in a 540 has 67.5 cubic inches.
    theres 8 cylinders that need 67.5 cubic inches of air volume 3675 times per minute.

    but remember an intake port and intake valve ,flows air during about 250 degrees in a 720 degree cycle, thats about 35% -40% of the time,the engines intake valve is effectively open and flowing air, and remember the exhaust scavenging,
    has a huge effect on intake flow rates.
    lets look at an intake port that flows 400 cfm which you might need to allow a 540 to flow enough air because even if the heads potentially flow 400 cfm the intake manifold or some other component may not fully keep up!
    flow rates are measured on a flow bench at constant flow rates,
    but theres 61.25 intake strokes per minute, per cylinder.
    in theory a port that flows 400 cfm will flow about 160 cfm during the 40% of the time its open in the 720 degree cycle. thats 160 CFM x 144 cubic inches,
    23040 cubic inches
    /61.25 intake strokes per minute= 376 cubic inches

    376 cubic inches x 61.25 intake stroke per minute +23039 cubic inches


    Last edited by a moderator: Jun 18, 2017
  5. grumpyvette

    grumpyvette Administrator Staff Member


    Dr J's pump gas 496 BBC
    496 pump gas BBC 765hp!!
    4.310 bore X 4.25 stroke
    probe 18cc dome shelf pistons 11.10 to 1 compression
    Scatt 4340 crank and H beam rods
    Custom Isky solid roller .750 lift intake .720 lift exhaust 270/274 @ .050 108 lca
    Jesel Sportsman rockers

    AirWolf 305 CNC ported oval port heads(edelbrock castings)
    2.300 intake and 1.900 exhaust valves
    109cc chambers

    Ported Dart 4150 intake with 4500 adapter
    Dr J's 1150 4500 carb
    VIDEO ... r_embedded

    The AIRWOLF 305 Oval Port is finally done. the great thing about this program is we can put this port in any oval port Performer RPM head. there are 3 different chambers 105cc, 110 and 115cc. The Edelbrock head has a stock exhaust port location, it sure makes the header fitment alot easier for the muscle car guys

    Based on a Edelbrock 6046 oval port RPM casting.

    Flow numbers
    Tested on a 4.310 bore @ 28"
    2.300 intake 1.88 exhaust

    Intake CFM
    0.100 74 cfm
    0.200 145 cfm
    0.300 225 cfm
    0.400 286 cfm
    0.500 329 cfm
    0.600 355 cfm
    0.700 374 cfm
    0.800 381 cfm
    0.900 387 cfm
    1.000 396 cfm

    Tested with a 2"x3" stright wall pipe
    Exahust CFM
    0.100 62 cfm
    0.200 123 cfm
    0.300 165 cfm
    0.400 190 cfm
    0.500 215 cfn
    0.600 235 cfm
    0.700 254 cfm
    0.800 271 cfm
    0.900 287 cfm
    1.000 299 cfm


    related threads
    Last edited by a moderator: Jun 20, 2018
  6. grumpyvette

    grumpyvette Administrator Staff Member

    heres limited but useful info on a similar build

    492 BBC
    BG 825 mighty demon
    RPM AirGap
    ProComp oval port heads
    10.5:1 CR
    Ultradyne solid roller 287/295 adv, 256/264 @ 50, 660/660 lift, 110 lobe sep (same as Lunati 502A4)
    2 1/4 dyno headers

    669hp @ 6400
    631tq @ 3800

    HERES A DIFFERENT 496 big block build

    4.310 Dart Big M - 0 deck
    4.25 / 6.385 forged crank/rods
    SRP 18CC pistongs
    AFR 315 CC Heads milled to 115 (Thanks CSTRAUB)
    Jessel Sportmans 1.7 rockers (Thanks CSTRAUB)
    Custom Bullet Cam (Thanks CSTRAUB) 267/274 @ 0.50 712/685 on 108 LSA.
    Morel SR lifter (Thanks CSTRAUB0
    Victor JR
    Pro-Systems HP1000
    1 inch spacer

    EngSpd STPPwwr STPTrq A/F AF1 LamAF BSFC Air_1 VoIEff
    RPM CHp Clb-ft RatiO ratio ratio lb/hph CFM %
    4300 501.4 612.4 13.6 13.2 14.2 0.448 665 107.7
    4400 507.1 605.3 13.7 13.2 14.1 0.443 670 106.1
    4500 521.2 608.3 13.7 13.2 13.9 0.440 684 106.0
    4600 538.2 614.5 13.7 13.2 13.9 0.437 702 106.2
    4700 557.1 622.5 13.8 13.1 13.9 0.434 724 107.3
    4800 575.2 629.3 13.8 13.1 13.9 0.432 748 108.6
    4900 590.9 633.4 13.9 13.1 14.0 0.431 770 109.5
    5000 605.8 636.4 14.0 13.1 14.0 0.430 793 110.6
    5100 619.2 637.7 14.1 13.1 13.9 0.430 819 111.9
    5200 632.1 638.5 14.2 13.1 13.9 0.430 841 112.6
    5300 645.1 639.2 14.4 13.1 13.9 0.430 867 114.0
    5400 655.7 637.8 14.5 13.2 13.9 0.431 890 114.8
    5500 666.3 636.3 14.6 13.2 14.0 0.433 911 115.4
    5600 675.7 633.7 14.6 13.3 14.0 0.436 934 116.2
    5700 684.4 630.6 14.6 13.4 14.0 0.441 957 116.9
    5800 693.0 627.6 14.6 13.4 14.0 0.446 979 117.6
    5900 700.9 623.9 14.7 13.3 13.9 0.449 1000 118.1
    6000 707.9 619.7 14.7 13.3 13.8 0.453 1022 118.7
    6100 715.5 616.1 14.8 13.2 13.8 0.454 1035 118.2
    6200 721.7 611.3 14.8 13.2 13.9 0.456 1051 118.1
    6300 726.9 606.0 14.8 13.2 13.9 0.458 1065 117.8
    6400 729.3 598.5 14.8 13.2 13.9 0.464 1080 117.5
    6500 732.8 592.1 14.7 13.2 13.9 0.469 1092 117.0
    6600 735.3 585.1 14.7 13.3 13.8 0.475 1105 116.6
    6700 736.9 577.7 14.6 13.3 13.8 0.481 1117 116.1
    6800 737.4 569.6 14.6 13.4 13.7 0.488 1129 115.7
    6900 735.5 559.8 14.6 13.4 14.2 0.497 1142 115.3
    7000 734.6 551.2 14.7 13.3 13.7 0.497 1152 115.6
    7000 737.4 639.2 14.8 13.4 14.2 0.497 1152 116.7
    Last edited by a moderator: Jul 3, 2016
  7. grumpyvette

    grumpyvette Administrator Staff Member

    [​IMG] ... 3454&dds=1
    http://www.compperformancegroupstores.c ... gory_Code=
    CRANE 138361 solid roller cam

    496 VERSION
    540 version

    Btw heres a tip learned through experience , if your 496 -540 displacement BBC combo includes an engine with at least 10:1 compression and a cam with at least 240 duration at .050 lift, and oval port heads, youll almost always find a single plane intake has some advantages over a dual plane intake.

    heres several related threads with big block combo results and parts lists etc.
    obviously most are race combos not designed for street use but some of the infos valid

    after reading thru the thread Id just want to state a few points

    (1) software dynos can be useful but don,t even think the actual predicted hp/tq numbers will be exactly accurate

    (2) no hydraulic roller cam in my experience is worth a damn over about 6400 rpm compared to a decent solid roller cam, but on a street car mid range torque is far more useful

    (3) guys commonly make the mistake on big blocks of selecting a 112-114 LSA ,with a good deal of duration, big blocks are UNDER VALVED, and a tighter 106-108 LSA and slightly less total duration almost always works better

    (4) try and get your dynamic compression in the 8:1 range and your quench down in the .038-.044 range

    (5) on a 468-496 bbc a 290cc oval port heads fine on a 540 Id be inclined to select a 315-335 cc port head,.

    (6)both the intake and header design have a very pronounced effect on your effective head and runner flow rates, a tighter LSA can benefit from the more efficient flow during overlap

    (7) a strong ignition and controlling both the advance curve and fuel/air ratio is critical.







    IF YOUR PLANING ON SUPERCHARGING A BBC< I think that reading these linked articles might help ... ewall.html ... ewall.html ... let_heads/ ... ewall.html ... ewall.html ... ewall.html

    Last edited by a moderator: Jul 25, 2017
  8. grumpyvette

    grumpyvette Administrator Staff Member

    pretty basic combo,
    off the shelf Scat 4340 profiled crank,
    Scat 6.385 H beams,
    SRP#212157 pistons,
    Moroso windage tray,
    Milodon Chevelle pan.
    1989 .060 454 block,
    ARP main studs,
    a Jomar rocker stud girdle
    mains line honed.
    Cometic head gaskets,
    ARP head studs
    . Oval port Weiand Team G ported to the heads.
    Holley ultra HP 1050 Dominator reworked from Racecraft Racing Carburetor's
    . Cam is a custom Comp solid roller .726in/.705ex, 252in/258ex @.050.
    This thing idles like a Cadillac, but revs like a pro stock..very happy with it!! ... r_embedded

    (looking at the A/F ratio chart ID expect power could be increased slightly with a slightly richer set of jets to get the F/A ratio closer to 12.8:1-13.3:1 in the 4500rpm and above range)
  9. grumpyvette

    grumpyvette Administrator Staff Member

    4.31x4.25 496bbc
    Mahle pistons 10.8:1
    Scat crank/rods
    Milodon 31188 oil pan
    Solid roller .731/.715 268/278@50 108lsa
    GM 781 ovals 2.25x1.88 (seriously professionally ported)
    Victor Jr 454-O
    Holley Aluminum Ultra-HP 950 carb
  10. Indycars

    Indycars Administrator Staff Member

    The BSFC looks unreasonably low, most numbers I've seen range in .45 to .55 area. Are these too low to be valid numbers ???

    I didn't know what the BSAC was about, but I found this article that explains it and does a good job of explaining what you need to know about using numbers from a dyno test. ... iness.aspx


    Attached Files:

  11. grumpyvette

    grumpyvette Administrator Staff Member


    , GOOD CATCH! and I DON,T KNOW THE ANSWER , WHY IN THIS CASE, I just re-posted what he posted, your correct those numbers do look rather low, and your correct normal is in the .45-.55 range, but looking at the fuel/air ratio, over most of the rpm range tested, he tends to be running a bit leaner than ideal, in the 13:1-14.7:1 range also, most guys want to stay in the 12.4:1-13.5:1 f/a range on max power combos, because it tends to produce better torque numbers and have a lower tendency to get into detonation when your fuel/air ratios closer to 12.4:1-13.5:1 f/a range

    AS your link says

    "BSFC refers to Brake Specific Fuel Consumption and is typically shown at each data point. The units are normally in pounds per horsepower hour (lbs/Hp-hr). This reference is essentially how efficiently liquid fuel is turned into horsepower. A common target for gasoline fuel is about .5lb/Hp-hr. Don’t get fooled into thinking that the BSFC number is either rich or lean. That is not correct and will lead to errors in analysis.

    BSAC refers to Brake Specific Air Consumption and is displayed at each data point. The units are normally in pounds of air per horsepower-hour and indicate the use of air and how efficiently the engine made power with what it consumed. "
  12. grumpyvette

    grumpyvette Administrator Staff Member ... index.html

    Scat Rod Specifications
    Connecting Rod Length Center to Center 6.385 inch
    WristPin Style Floating
    Connecting Rod Bolt Diameter 7/16 inch
    Rod Journal Diameter 2.200 inch
    Big End Bore Diameter 2.3250 inch
    Pin End Bore Diameter 0.990 inch
    Big End Width 0.992 inch

    Cam specs
    Type Roller Mechanical Roller
    Valve Lift 0.714/0.710
    Duration at 0.050 270/280
    Lobe Separation (degrees) 110
    Basic rpm Range 4,800-7,200
    Intake Duration at 0.050-inch Lift 270
    Exhaust Duration at 0.050-inch Lift 280
    Advertised Exhaust Duration 315
    Intake Valve Lash 0.024
    Exhaust Valve Lash 0.026

    Read more: ... z1qebVoyKi
  13. Indycars

    Indycars Administrator Staff Member

    What I found interesting were the roller lifters and their adjustable oil flow to the top end. But at a Summit price of $937, it don't come cheap!

    Quoted from CHP

    hese COMP Cams Elite Race solid-roller lifters are trick and come with a myriad of features. Some of these are the exclusive body design that don’t include an oil band, which maximizes rigidity and reduces lifter bushing wear. The body is manufactured from CNC-machined SAE 8620 steel alloy, with steel alloy wheels that have been micro-polished and micro-sized and needles that are made from 52100 bearing steel and micro-sorted with a controlled contour profile. While the construction and body design make them incredibly strong, they are also lightweight, with each lifter weighing less than 100 grams. They also have oversized (0.400-inch) axles that are dual-pinned, have captured link bars and an exclusive modular pushrod design that allows the pushrod insert to be swapped out for centered, left, or right offsets. These lifters also have a patent-pending oil control through the pushrod insert; engine builders can modify the lifters to meter extra oil to the top as desired.


    Attached Files:

  14. grumpyvette

    grumpyvette Administrator Staff Member

    BE aware you need to verify rocker adjustment lock nut to rocker slot clearance and yes it varies even with the same manufacturers different rocker designs
    heres a bit of useful related push rod length info
    Big Block Chevy, Standard Length Big Block Intake 3/8" / .080" 8.275"
    295-7941-8 Big Block Chevy, Standard Length Big Block Exhaust 3/8" / .080" 9.250"
    295-7969-8 Big Block Chevy, Standard Big Block +.100" Long Intake 3/8" / .080" 8.375"
    295-7979-8 Big Block Chevy, Standard Big Block +.100" Long Exhaust 3/8" / .080" 9.350"
    295-7951-8 Big Block Chevy, Standard Length Big Block Tall Deck Intake 3/8" / .080" 8.675"
    295-7961-8 Big Block Chevy, Standard Length Big Block Tall Deck Exhaust 3/8" / .080" 9.650"
    295-7800 V8 396-454 Retro Fit Pushrod Set, Intake & Exhaust, 1965-Present
    3/8" / .080"
    3/8" / .080" 7.725 Int.
    8.675 Exh
    295-7913-16 Small Block Chevy, Standard Length Small Block Chevy 3/8" / .080" 7.800"
    295-7984-16 Small Block Chevy, +.100" Long 3/8" / .080" 7.900"
    295-7934-16 Big Block Ford, Standard Length Ford `72-'78 429-460 3/8" / .080" 8.550"
    295-7951-16 Big Block Ford, Standard Length Ford `69-'71 429-460 3/8" / .080" 8.675"
    295-7582-16 Oldsmobile, Std Length 455 5/16" 9.550"

    Hi Guys,

    I have finally got my 496 finished and dyno'd.

    I built this motor my self, with a lot of research on here as well as with a lot of help from Mike Lewis and Chris Straub, In the way of supplying parts and Giving great advice . I couldn't have done it without their help.
    Thanks guys.
    The specs of the engine are
    Mark4 4bolt block, .060 over with
    Mahle forged pistons for 10.9 comp and
    Eagle forged h beam rods
    and 4.25 forged crank.
    The heads are AFR 325 with cnc chambers,
    ARP head studs and main bolts
    with comp ultra pro magnum roller rockers.
    I used a Victor 454R and a Pro systems 1050 Dominator.
    We tried a new holley 950 ultra hp but the dominator made more power.

    The cam Chris supplied is a custom Bullet grind solid roller with .264 @ .050 and .711 lift and .272@ .050 and .650 lift. I also used Isky needleless roller lifters.

    The springs that came with my heads as set up for the solid roller proved not to be up to the job. They measured 290 on the seat and 750 over the nose. We had a valve float issue with power falling off really fast after peak power and a marked dip in power at about 5800rpm. After pulling a few springs there was chatter marks under the retainers and on the spring cups and wear marks on the locks where they had been floating in the retainers.

    We had close to .250 too bind clearance so we reduced that by about .140, giving it about 360 on the seat and 850 over the nose as measured.
    So now with these spring pressures i think i will eventually get a set of shaft rockers.


    Last edited by a moderator: Jul 23, 2017
  15. grumpyvette

    grumpyvette Administrator Staff Member

    I know most guys work on very limited budgets and a flat tappet solid lifter cam, and matched springs can easily cost $600-$1200 less than a similar roller cam making that at least for most guys an option, on a tight budget, so heres some info.heres a couple fairly cheap, flat tappet solid lifter cams
    Ive found work rather well in most 467-540 big block muscle car engines, as long as you have a decent 3.54:1-4.11:1 rear gear ratio, a manual transmission or a matched stall speed converter and at least 10.5:1 compression and a good intake, headers etc.
    obviously youll want to have a long discussion with your engine builder and the cam manufacturer before selecting one and be aware that a solid or hydraulic roller lifter cam may be a better but more expensive option

    youll really want 11:1-12:1 compression ratio, a manual trans, a 4.11:1 rear gear and open headers and a single plane intake on a 496-540 displacement to let this cam above breath. a decent cam in a tunnel ram intake and it just keeps pulling even past 6500rpm-7000rpm plus in a serious high compression 496-540 bbc
    the cam below is basically a slightly milder version, and works fine in a similarly built 467-496 BBC built to the tips above, but neither cam is ideal in a street car.
    THIS CAM ABOVE IS USUALLY A GOOD CHOICE IN A SERIOUS STREET/STRIP PERFORMANCE 496BBC build if you have at least 10.5:1 cpr, a dual plane intake and a manual trans with a 3.73:1-4.11:1 rear gear, its the cam I usually select if I know the guys 90% street driven, in a camaro or nova with a manual trans 467-496 BBC
    lots of guys like this in a 10.5:1 compression 496 with a dual plane intake for a street muscle car, its got a lopey idle that many guys want, and still has decent low and mid rpm torque

    related threads





  16. Michael

    Michael Active Member

    Not sure if this is the ideal context in which to ask, but for years I've been wondering about Vizard's ubiquitous chart on LSA vs. ratio of cylinder displacement to intake valve area. I think that usage of such a chart tends to result in selecting cams with excessive overlap. For a 496 with 2.25" intake valves, this ratio is about 27.5, putting Vizard's recommended LSA at around 101 degrees! Now combine that with a moderate mechanical roller cam - say around 240i/250e duration at 0.050" (fairly conservative for a 496 with around 280cc intake-volume oval port heads and ~ 10:1 static compression) - and we get humongous overlap.

    I'm a skeptic of performance-calculators, but they have their uses. Plug such a combo into the typical calculator and see what happens to the torque curve. Then increase LSA bit by bit, and watch that torque curve change. In light of that, do Vizard's recommendations make sense for non-race large-displacement 2-valve engines? Thoughts?
  17. grumpyvette

    grumpyvette Administrator Staff Member

    I think a bit of context helps here, nearly every choice in components you select has some effect on how the other components will function, I looked at that chart and had a similar reaction when I calculated what was required and found the answer to the suggested LSA was a good deal tighter than Id expected it to be, but I have found that dropping back to a tight 105-106 LSA and selecting a bit LESS total duration DOES tend to get better results that the typical 110-114 LSA and a longer duration combo, I think the problem many guys have is that for years they were using lets say a 250/260 duration cam on a fairly wide LSA and when they calculate what they need the find it might be a 245-250 duration on a 104 lsa and they instantly think, that can,t be correct thats less duration than Im using now!
    what further aggravates the problem is most software dyno software doesn,t take into account that extending the over lap IF YOU HAVE CORRECTLY DESIGNED HEADERS, tends to noticeably increase the headers ability to scavenge the fuel/air charge in the cylinders , leaving less exhaust from the previous combustion cycle.
    also keep in mind that peak horse power is not necessarily the only goal, I think the idea is to maximize the mid and upper rpm torque curve.
    the short answer is that Ive found a tighter LSA AND A BIT LESS DURATION IF MATCHED TO A CORRECTLY TUNED SET OF OPEN HEADERS AND A DECENT INTAKE, does tend to work rather well as the chart predicts but as in all things you need to make some compromises, on a 496 bbc Ive consistently gotten better results with a fairly tight 105-108 lsa that with cams having a bit more duration with similar overlap numbers and a wider 110-112 lsa. but remember the cam alone doesn,t control the results, your intake and exhaust components can also effect results, and those tend to change at different rpm levels.
    now Im not saying you can,t build a good running combo using a 110-112 lsa cam, but Its been my experience that selecting a cam with a bit tighter LSA and a bit less duration does have some benefits in bumping up the average ft lbs in the torque curve in many 496 BBC combos, and yes, ID BE FIRST IN LINE TO SUGGEST THAT YOU OTHER COMPONENTS BEING SELECTED DO EFFECT THE RESULTS, AND THAT SIMPLY SELECTING A CAM WITH A TIGHTER LSA IS NOT NEARLY ALL THERE IS TO BUILDING A KILLER 496 BBC.


    very common mis- conception, is that a cam which is ground on a 108 degree lobe center. which has more overlap and will reduce your DCR due to greater overlap."

    ( is that overlap with a tight LSA bleeds off compression)
    Overlap has nothing too due with DCR. A cam with 108 LSA will close the intake valve sooner on the compression stroke and create MORE cylinder pressure than a cam with 112 LSA. if both have identical duration, That assumes durations and cam lobe designs are the same of course "

    this is correct

    LOOK heres TWO cams IDENTICAL EXCEPT FOR THE LSA,(LOBE SEPARATION ANGLES) assuming both cams are installed with identical LCA (LOBE CENTER LINE ANGLE)remember lobe center angles can be changed thru indexing the cam when degreeing it in, LSA is ground into the cam during manufacture, the tighter LSA of the crane 110921 builds a bit more cylinder pressure and results in slightly more torque over a NARROWER rpm band so its better with a manual transmission, the crane 114681 with its wider LSA tends to work better with an auto trans with its wider torque band but very slightly lower peak torque, the crane 110921 has more overlap and better scaveging in the mid rpm band, but it idles rougher at low rpms and that overlap doesn,t help if you use nitrous

    narrower LSA, more overlap & more effective compression, because the intake valve closes earlier
    wider LSA, less overlap & less effective compression, because the intake valve closes later



    when your reading a cam spec card, you'll want too keep in mind theres 720 degrees in a cycle and the cam turns at 1/2 the speed of the crank so the piston reaches TDC twice in one complete rotation of the cam, plus cam cards generally start with the exhaust valve opening not the intake valve as most of us might assume

    do yourself a favor and invest in a few books and READ THRU THEM,as reference before beginning the project, if you spend a few days doing research here youll save a good deal of time and wasted effort

    Last edited by a moderator: Aug 6, 2017
  18. Indycars

    Indycars Administrator Staff Member

    Thought it would be easier to see if the graphs were pasted one on top of the other.

    When I used the Waller calculator to get LSA and Overlap, I got something completely
    different for Overlap than the 36° & 24° shown in your Dyno2000 info ???

    Waller Calculator:


    Attached Files:

  19. Indycars

    Indycars Administrator Staff Member

    Reading the graph, it looks like the 110921 has less torque. Did you somehow get these reversed in your statement ???


    Attached Files:

  20. grumpyvette

    grumpyvette Administrator Staff Member

    yes Im only two well aware of what the graphs the software dyno predicts ,tells you, too expect.
    both cams make similar power levels but the 110921 tends to come in about 300 rpm faster and peak about 300 rpm lower in my experience, making it a better choice for a manual transmission car, because its easier to use once you learn to match your driving and shift points to the engine characteristics, the 114681 has a noticeably smoother idle, it pulls well thru most of the rpm range and its not as hard to tune the car, so its a better match for an auto trans where the typical drive style is point,the car, in the intended direction, floor it, and hold on.
    but my real world results have been a bit different, the engines Ive used the cranes 110921 were both more responsive and made a bit more mid rpm torque and a bit less peak power at the cost of a distinctly rougher idle , this is a good example of why experience and software don,t always agree

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