building a TALL DECK BBC

grumpyvette · Sep 21, 2008

got a truck block? want a 496 vs a 427
if you have or can purchase a tall deck 427 bbc engine..there are potential mods you can make..
Chevy Performance BBC Bow Tie Race Engine Blocks | JEGS

Cast Iron Bow Tie Race Block Technical Notes
Precision CNC-machining means +/- 0.001'' tolerances
Standard deck (9.800'') or tall deck (10.200'')
4.240'' Finish Bore (4.600'' Maximum Bore, .250'' Minimum Wall Thickness)
A sonic bore check data sheet is provided with each block
Lifter bores are .300'' taller than standard blocks
Siamese cylinder bores
Improved cooling around number 1 cylinder
Accepts Mark IV or Gen V, Gen VI cylinder heads
Use Gen V head gaskets with Mark IV and Gen V cylinder heads
Use Gen VI head gaskets with Gen VI cylinder heads
Requires Mark IV design 2-piece rear main seal oil pans
Requires Mark IV design crankshafts
Can use Mark IV and Gen V, Gen VI camshafts, timing sets, lifters and timing cover
(aftermarket belt drive timing covers may require clearancing)
Blind-tapped head bolt holes; extra inner head bolt bosses provided
4-bolt SAE 8620 main caps splayed 16° on the three center mains
Priority main oiling wet sump system
Provisions for dry sump oil line provided
Honed camshaft and crankshaft bores
0.842'' lifter bores (maximum 1.06'') may be relocated
Distributor gear clearance at bottom of number 8 cylinder bore should be checked
Machined mechanical fuel pump pad
Tested to 1,200 horsepower!
http://www.strokerengine.com/DartBBC.html

http://reviews.ebay.com/ebaymotors/Big- ... 0001563647

http://www.dragzine.com/tech-stories/en ... ine-block/

viewtopic.php?f=87&t=951&p=3757&hilit=tall+deck#p3757

viewtopic.php?f=51&t=3817&p=10148&hilit=tall+deck#p10148

viewtopic.php?f=51&t=2692&p=8174&hilit=tall+deck#p8174

now Im well aware most of you may not ever use a bbc engine, but if you do...heres some info
IF the rest of the basic engine is servicable,Id rebuild it with a mild port clean up,a valve job,a re-ring and new bearings, plus the tall deck block allows you to use longer connecting rods and a 4.25" stroke crank, to build a 496 displacement 10:1 cpr engine ,youll need the block bored and honed at .060 over(4.310 bore) done very easily,just the increase in displacement and compression (with the correct, crank, rods and pistons) matched to a reasonable cam will make a very noticable power increase
kits like this are available for the standard 9.8" blocks
DART BIG M BBC BLOCK
Features:

Siamesed Extra-Thick Cylinder Walls: Resists cracking and improves ring seal (minimum .300'' thick with 4.625'' bore).

Scalloped Outer Water Jacket Walls: Improves coolant flow around the cylinder barrels to equalize temperatures.

Four-Bolt Main Bearing Caps: In steel or ductile iron have splayed outer bolts for extra strength.

Crankshaft Tunnel: Has clearance for a 4.500'' stroke crank with steel rods without grinding.

True ''Priority Main'' Oil System: Lubricates the main bearings before the lifters.

Oil Filter Pad: Drilled and tapped for an external oil pump.

Rear Four-Bolt Cap: Uses standard oil pump and two-piece seal - no adapter required!

Lifter Valley Head Stud Bosses: Prevent blown head gaskets between head bolts.

External Block Machining: Reduces weight without sacrificing strength.

Simplified Install : Fuel pump boss, clutch linkage mounts and side & front motor mounts simplfy installation on any chassis.

Dual Oil Pan Bolt Patterns: Fits standard and notched oil pans.

Bellhousing Flange and Rear Main Bearing: Reinforced with ribs to resist cracks.

Note: Does not include cam bearings, freeze plugs, or dowels

http://www.sallee-chevrolet.com/Sca...embly_Kits.html

crank rods. pistons, ballanced for about $1400
add a cam like this
http://store.summitracing.com/default.as...p;x=29&y=14

and with no other changes to the basic engine youll have a noticable power increase
Id expect to spend under $3000 and have a reasonably effective street combo

but since your useing a tall deck block youll want to purchase all the parts seperately

chevy has produced two comon bbc block heights, the comon pass car 9.8" deck block and the taller less comon 10.2" truck block, truck blocks allow more clearance but they move the heads further appart so spacers or differant intakes and a few other parts are necessary, I personally PREFER truck blocks as they tend to be thicker and cheaper, as fewer people want to use them

it should be OBVIOUS that youll need to do a MINIMUM of homework BEFORE ordering parts for a 496 bbc stroker kit to fit a tall deck block

here this calculator will help
http://kb-silvolite.com/calc.php?action=piston_comp

the standard BBC has a 9.8" deck height, the TALL block has a 10.2" deck thats .400 taller, so youll want to use standard 454 pistons to keep the cost low and make up the differance in connecting rod length for a better rod/stroke ratio.
keep in mind youll want to use longer rods and lighter pistons for a better rod/stroke ratio WITHOUT getting into CUSTOM parts
the comon longer than stock,bbc rod lengths available are 6.385",6.585",6.8"

BUT ,look a standard 454 bbc has a 4" stroke, 6.135 rod and a 9.8" deck so the pistons got a 01.665" pin height the same block with a 3.76" stroke crank from a 427 would use a 01.785 pin height, neither will work in a 4.25" stroke 10.2" deck block application

these pistons below have a 1.27 pin height

http://kb-silvolite.com/performance...ls&P_id=358

the tall deck with its 10.200 deck and a 1.27" pin will require a 6.8" rod

http://store.summitracing.com/default.as...p;x=35&y=14

1.27"piston pin height, + 6.8" rod length + 1/2 of 4.25" stroke(thats 2.125") equals 10.195" or .005 below the 10.2" deck on a tall deck block
thats a 1.6:1 rod/stroke ratio, or close to the 1.63:1 a 350 chevy has and better than the original 454s 1.53:1 ratio, even thought the strokes been increased

a combo like that should exceed 550 ft lbs and 500hp easily

WANT TO GO NUTS WITH YOUR WALLET SCREAMING FOR MERCY?
http://www.hotrod.com/techarticles/engi ... index.html

grumpyvette · Dec 21, 2008

greg_moreira posted this
"I cant pinpoint an exact displacement limit.....but it sure appears that about a 540 incher is the way to go. Beyond this point(displacement wise), you just dont hear about a lot of them lasting the duration.

Im sure half the reason is because of the radical gathering of parts you need to get a 600 plus incher to breath and make rpm. Rightfully so as well.....why waste the time and money to go all out on huge inches, but then feed it with mild stuff that wont make rpm. So yeah....If I ever were to consider a 632 for instance, everything else that goes with it would be rad. And it probably wouldnt last real long either no matter which what it was built.

But, the 496-540 variety has proven to be real capable of reliability. Breakage can still happen if you build it super rad, but there are a lot of em out there that dont need to ever go over 6500 revs and peak in the neighborhood of 700 horses at around 6100 or so. In something like this, the shortblock can last a long time, and so can everything else with proper parts selection.

In all reality, if you build a true 700 horsepower ground pounder, you probably didnt have plans of only driving on the street and driving every day. Chances are its a toy to drive a couple times a week and at least race a couple times a year.

So if you put 2500 miles a year on it(and thats a lot for some people)....it might go 3-5 years before your in a position where you actually need new springs and lifters. Thats not a bad maintenance record considering the 10 second, if not high 9 second potential in most any vehicle as well as enough street manners to enjoy driving a couple times a week or so.

If you build it a little milder say at 550 horsepower and drive it constantly...you may have to replace less stuff less often...but you will just go through way more tires and gas, so it evens out anyways hehe. And if you build it huge, you just run the risk of more breakage more often like these huge engines just seem to do. One guy had a quote that sticks into my head. Cant exactly remember the conversation or exactly how this quote made its way into the conversation, but it did have something to do with reliability and big inches, and the guy added to the conversation..."God hates a 632". It made me laugh, and it also seems like there is some sort of truth to it.

540 s the biggest Ill go for a driver of any kind. "

Limey Tri Chevy posted this
"
I spoke at length with Mike at Scott Shafiroff race engines about this very subject. I wanted a blown 572ci because 'everyone' had a 540ci engine. He explained that to achieve this in a standard deck height engine would compromise the strength of the crown as the pin would have to encroach too much into the piston, especially in a blown or nitrous application. They would work fine for a torquey big inch normally aspirated engine but not one with lots of boost / cylinder pressure. He said that 'everyone had a 540ci with a blower for a reason. They make lots of power and are easy on parts. If I wanted a 572ci I would have to go tall deck and add 70lbs to the nose of the race car. That would negate any extra torque the bigger engine produced at more cost $$$'s to me.

They are building me a standard deck 540ci long block designed for a blower that can stand 1500bhp. I am adding an F2 cog tooth procharger which will make about 1200bhp at 24lbs boost on pump gas!! I will probably run it at 16lbs boost on the street which will equate to around 800bhp on pump gas. 1/2 what the engine is rated at so not stressing it at all.

I was told this engine if looked after will need regular oil changes, valve's checked every year with cam clearances and thats about it.

I thought I needed a big cube engine but a talk with a pro that was willing to take time out to explain gave me a different perspective and them a sale. Unlike some of the others who would build whatever I wanted regardless of whether it was best for the application and my pocket. "

grumpyvette · Dec 10, 2012

http://newcenturyperformance.com/Blocks.htm
theres a new source for tall deck aluminum big block chevy blocks
IF YOUVE GOT DEEP pockets
aluminum's FAR easier to repair once damaged as TIG welding ALUMINUM is far simpler than nickle brazing cast iron, aluminum dissipates heat faster, aluminum,s far easier to machine, and if your doing some mods you can weld stuff too aluminum far easier
but the cast iron blocks USUALLY got an edge in stiffness
the big problem is COST,

http://www.brodix.com/blocks/5inchblock.html

http://www.brodix.com/blocks/4.500block.html

http://www.dartheads.com/products/engin ... ig-blocks/

http://www.dartheads.com/products/engin ... locks.html

http://www.cnblocks.com/

http://garage.grumpysperformance.co...ing-to-partially-fill-coolant-passages.14545/

http://garage.grumpysperformance.com/index.php?threads/which-496-bbc-engine.12291/#post-60432

http://sdparts.com/details/gm-performan ... s/19170540

http://www.jegs.com/p/World-Products/Wo ... 3/10002/-1

Ansen 120-1003 Big Block Chevy Valve Cover Spacers

The perfect finishing touch for your engine.
www.speedwaymotors.com

https://www.amazon.com/Holley-89000...bf-b4db-ddf2adfde0b0&pd_rd_i=B01LWNH13A&psc=1

Valve Spring Cooling via Engine Oil

Grumpy: Read your post on the subject of Valve Spring Cooling with Engine Oil. Thanks VERY MUCH for bringing this to my attention. I have built a SBC 383 stroker going into a 1971 Datsun 240Z. Used a shaft rocker setup, but am uncertain that the trunion is being lubricated via Engine Oil...
garage.grumpysperformance.com

https://www.amazon.com/Block-Valve-Cover-Spacer-551640-7/dp/B00NY4VP62

several options exist, in valve cover spacers, and taller valve covers ,obviously. clearance, quality features, and price varies

http://www.hardin-marine.com/p-12519-bb ... ystem.aspx

valve cover gaskets

a few things you should know Ive had the best luck with the extra thick synthetic /cork composite mix gaskets http://store.summitracing.com/partdetail.asp?part=FPP-1604&autoview=sku http://store.summitracing.com/partdetail.asp?part=FPP-1630&autoview=sku...
garage.grumpysperformance.com

oil system mods that help

heres a short list REMEMBER the object or goal in building and maintaining the lubrication system is too maintain a 100% dependable pressurized cooling flow of lubricant to the bearings, rockers,valves etc. obviously use of a high quality synthetic oil that has a higher heat tolerance and that...
garage.grumpysperformance.com

catch can related info

In every engine a small amount of pressurized gases from combustion pressure, during the engines power stroke that's been generated is getting past the rings, as the compression and combustion stroke begins before that cylinder pressure forces the rings out against the cylinder walls. and it...
garage.grumpysperformance.com

valve cover install

Most guys with corvettes stay with the stock valve covers unless forced into swapping , due too clearance issues caused by the need to use roller rockers, stud girdles or other aftermarket valve train accessories. On some corvettes theres serious clearance issues with the windshield wiper motor...
garage.grumpysperformance.com

ICT Billet 551640-5: Valve Cover Spacers for Big Block Chevy - JEGS High Performance

Buy ICT Billet 551640-5 at JEGS: ICT Billet Valve Cover Spacers for Big Block Chevy. Guaranteed lowest price!
www.jegs.com

87vette81big · Dec 12, 2012

I have a Tall Deck 427 BBC Longblock put away Grumpy.
Have been saving it for a project someday.
Missing the intake & carb, no balancer, flywheel or accessory brackets.
Bought it back in 2000 while working in a Now defuct closed down GM Dealership as a line mechanic.
Snagged it up for $100. Came from a 1990's GMC Kodiak Truck. Not many miles, all original GM Black paint still intact & no rust.
Engine ran but used 1 quart of oil every 3,000 miles & customer did not like that. So he ordered a brand new GM Crate engine & had it installed.
I have thoughts of using the 427 Tall Deck in my 1994 GMC Suburban. Give it real passing & towing power on the highway.
427 Tall Deck BBC's all have forged steel cranks & 4- bolt mains on all 5 I believe, maybe center 3 like a Pontiac V8 with 4-bolt mains, & factory double roller timing chain.

BR

grumpyvette · Dec 12, 2012

Ive built several 496 strokers using the tall deck blocks (I actually prefer them) theres plenty of intakes available, and some, of those intakes even allow the stock distributors from the standard deck blocks to be used, but your best served with an adjustable sliding collar distributor so you can exactly match the distributor shaft height required.
the main advantage of the taller block height is that you get to use a longer stroke and longer connecting rod lengths to keep the rod angles semi efficient, reducing side loads on the pistons slightly, and the piston skirts much more easily clear larger counter weights and the blocks will frequently allow installing a 4.25" stroker crank , with 6.385" rods, that fits with little or minimal clearance work, so in effect a 496 BIG BLOCK stroker is EASIER to build and makes far more power than a similar SMALL BLOCK 383 WOULD.
some people are concerned with the increased size of the engine, the taller deck height is sure to cause, the difference is less than most people imagine , the engines outside dimension change is about 5/8" taller and wider, with similar components used.
yeah! all it takes is a bunch or spare cash! to turn a 427 tall deck lower compression truck engine into a higher compression torque monster, but a good 4.25" or even a 4.375" stroke crank usually can be fitted and clearanced to work in the older tall deck blocks, just be aware that the lower oil pan rail has an oil passage you can,t grind into without trashing the block.
but with a great set of cylinder heads and a stroker rotating assembly , usually in the 10.5:1 or higher compression ratio range with the mandatory matched cam duration ,cam, the correct matched drive train gearing ,high capacity baffled 7-9 quart oil pan, etc upgrades, a stroker big block puts out impressive power numbers
(too bad its so damn hard to find and SPARE CASH! )

main_page=calculators&zenid=823ce2c9e2ffa691864d832c10107df0

the best solution from a performance perspective is to do the required calculations to select the longest length connecting rod and the lowest weight piston,
of a decent design that will reduce the reciprocating mass significantly more.
the tall deck has a 10.2" deck height, a good dual plane aluminum high rise intake manifold will tend to provide the best compromise if you use a low compression and mild cam duration,
while it might seem like a waste of time, now, reading the links and sub-links will provide a good base to work from, later and save you a great deal of wasted time and money
you have a choice, you can slap the components you own together, now and live with what you have built regardless of the results , or you can put some real thought into making the result perform and carefully select parts and significantly boost power... yes that routes more expensive up front, but in the long term it tends to get better results and cost LESS.
common BB CHEVY piston compression heights are
1.270"
1.395"
1.520"
1.645"
1.765"
remember the blocks deck height, minus the piston pin height minus 1/2 the crank stroke will equal the required connecting rod length
OR
the blocks deck height, minus the connecting rod length, minus 1/2 the crank stroke. will equal the required piston pin height

if you wonder why I suggest using SCAT (H) beam style cap screw connecting rods vs stock or most (I) beam designs this picture should show the increased cam to connecting rod clearance

notice the pin height in the pistons pictured above allow a longer or shorter connecting rod length

heres a selection of commonly available big block chevy connecting rod lengths

https://www.uempistons.com/index.ph...e=deck&zenid=823ce2c9e2ffa691864d832c10107df0

https://www.uempistons.com/index.php?main_page=calculators&zenid=823ce2c9e2ffa691864d832c10107df0
1.765 compression height, pistons in standard 9.8" deck block, a 10.2" tall deck requires a longer connecting rod
most likely a 6.535" aftermarket connecting rod

threads you should read through carefully,and the sub links in them are below,
the tall deck block is put to much better use building a 496 with a 4.25" stroke and a .060 over bore and 6.385" connecting rods

http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

http://garage.grumpysperformance.co...g-block-head-comparison.319/page-2#post-61658

http://www.maliburacing.com/patrick_budd_article.htm

http://garage.grumpysperformance.com/index.php?threads/427-tall-deck-bbc.14451/

http://garage.grumpysperformance.com/index.php?threads/big-block-chevy-info.710/#post-60299

http://garage.grumpysperformance.co...-displacement-street-engine.10961/#post-50668
THE LINKED related info, will prove very useful
viewtopic.php?f=69&t=5123

viewtopic.php?f=51&t=2692&p=8174&hilit=tall+deck#p8174

viewtopic.php?f=69&t=1420

viewtopic.php?f=69&t=3153

viewtopic.php?f=69&t=189

viewtopic.php?f=69&t=1059

http://www.popularhotrodding.com/tech/0 ... vy_engine/

http://www.summitracing.com/parts/mel-77060
you might want to read thru this thread
viewtopic.php?f=54&t=3536

IF you think your current distributor can, be used in a tall deck block engine build in most cases your usually going too need some mods , it can be easily modified by a local machine shop with a lathe for an adjustable slip collar by carefully machining off the current one and adding a slip collar, if you need to make distributor gear to cam gear engagement or oil pump drive shaft length changes, failure to get the distributor correctly seated will result in low or non-existent oil pressure

building a TALL DECK BBC

grumpyvette

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grumpyvette

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grumpyvette

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