building a high rpm 377sbc

[grumpyvette]

so you want a high rpm screamer, thinking about building,a 302 like the old Z28 engines?
well technology has advanced and theres better current options if your really interested
heres a mid priced effective combo

Ok time to get back to reality!
if your serious about building a high rpm screaming sbc I can,t think of anything Ive built or seen built that sounds better or pulls harder than a PROPERLY BUILT 377 , thats a 400 block with a 350 crank, it will spin at 7000rpm quite happily with a decent solid lifter valve train and the extra cubes more than compensates for the slight rpm advantage of the smaller 302.
obviously theres more expensive parts that could be used and those might increase the power some,or you could decrease the compression ratio down to about 10.5:1 to run on pump gas at the cost of some torque, but heres a decent combo
a properly assembled 377 will easily exceed 500 flywheel hp and have noticeably more torque than a similarly built 302, and before you ask it should be rather obvious that the engine built like that requires a proper quench and some bowl & chamber work and un-shrouded valves and its very unlikey to run on high test without some octane booster
cranes gold roller rockers are decent quality rockers for a small or big block chevy,Ive used those, ERSON, CROWER and COMP CAMS ROLLER ROCKERS, many of them come with jam nuts that require a 3/16" allen key
and look a great deal like these posted here below

but these are NOT locking jam nuts designed to work with a rocker stud girdle

http://www.summitracing.com/parts/tfs-3 ... /overview/
BTW.IF YOUR BUILDING A SBC
http://brodix.com/heads-2/small-block-chevrolet-compatible-heads/ik-series
http://www.jegs.com/i/Brodix/158/1021001/10002/-1

brodix ph# 1-479-394-1075 (ALWAYS VERIFY PART NUMBERS SEVERAL,
TIMES FROM AT LEAST TWO SOURCES, BEFORE ORDERING PARTS)
the brodix rock stud girdle is part # BR-6435 and LIST price is about $230 you can get it for less if you shop carefully
BE AWARE that the I.K. 200 heads were shipped with BOTH 3/8" and 7/16" rocker studs ,
and the poly locks for the 7/16" rocker studs ONLY fit that rocker stud girdle
obviously you need to verify what your heads have before you order the matching rocker stud girdle
Verifying your engines clearances, and rocker geometry, and use of A rocker stud girdle and high quality roller rockers go a long way towards maintaining valve train durability

rocker stud girdles require significantly longer shank jam nuts , but you need to mount the rocker stud girdle up out of the way so the upper surface of the rockers can,t touch the lower surface of the stud girdle at full lift

youll want a manual transmission and a 4.11-4.56 rear gear

heres a combo thats KNOWN to work

carb
http://www.summitracing.com/parts/HLY-0-4781C/

intake
http://www.summitracing.com/parts/HLY-300-110/

heads
http://www.summitracing.com/parts/BRO-1021001/

or
http://www.profilerperformance.com/sbc-heads-176.html

block
http://www.summitracing.com/search/?key ... 1211&dds=1

cam
http://www.crower.com/misc/cam_spec/cam ... 1&x=49&y=8 crower 00351

pistons
http://www.kb-silvolite.com/test/icon/i ... s&P_id=332

rods
http://www.summitracing.com/parts/SCA-26000716/

crank
http://www.summitracing.com/parts/SCA-435010/

use a rocker stud girdle it helps with high rpm valve train stability

long tube 1 3/4" tube headers that fit your application

a decent 7-8 qt baffled oil pan, that fits your application

http://www.moroso.com/catalog/categoryd ... code=11929

LINKS WELL WORTH THE EFFORT TO READ THRU


viewtopic.php?f=55&t=613&p=1379&hilit=+booster#p1379

viewtopic.php?f=53&t=726&p=5640&hilit=quench#p5640

viewtopic.php?f=52&t=727&p=6657&hilit=dynamic#p6657

viewtopic.php?f=52&t=2630&hilit=shrouding

viewtopic.php?f=54&t=2187

viewtopic.php?f=52&t=181

http://www.youtube.com/watch?v=i_NpzU4p ... re=related

you might want to watch these strobe light pictures of valves at higher rpms

obviously getting the clearances wrong, or over reveing the engine can cause problems

 

[dat260]

Hi Grumpy,
I want to build a high reving v8 for my datsun Z. I read a lot of posts on 302, 305, and 377. I have a few limitations because of my car and some drivetrain components. My Datsun is a unibody, I will install strut bars frt/r and beef up a liitle bit the front frame rails due to the v8 and a few braces here and there. I have an LSD 3.70 and it can handle 500 lbs and I can get a 5 or 6 speed trans. My concerns are, I like the 377 combo since block and crank can be found easily but i do not have 4.11 or higher gear, I like the 302 but high compression is no good for the local gasoline.
Do you have any other high reving v8 combos for my car? i do not street race or drag race. I do like to drive fast on long wide highways and I plan on racing it at ICAR, a local racetrack.
Cheers,

 

[grumpyvette]

thats a simple enough request, but remember for a street driven car youll be using the lower rpms a good deal more so while youll want to keep a fair bit of the upper rpm power youll also want to shift the power curve a bit lower.
everything you do will be a compromise in one or more areas,
Simply because you can,t spend 50% or more of your drive time with the throttle petal mashed firmly to the floor, and you won,t spend 90% of your timer above 4500rpm
for the street you can still build your 377 sbc with a bit less cam duration, a bit lower static compression and a bit higher port speed in the intake, use the same brodix 200cc heads

swap to a CROWER 00331 solid lifter cam

swap to a EDELBROCK AIR GAP DUAL PLANE INTAKE,its much better at producing low and mid rpm torque thru better volumetric efficiency due to higher port air flow rates and surprizingly not all that restrictive on peak power, yes youll be down a few peak hp, compared to the better high rpm flow rates of the single plane, but the dual plane more than compensates with increased torque below 5000rpm

http://www.summitracing.com/parts/hly-0 ... dia/images
swap to a 750cfm vacuum secondary carburetor, the vacuum secondary's make the car far easier to tune and drive at lower rpms at part throttle

build the short block WITH PISTONS TO MATCH THOSE HEADS TO GIVE YOU 9.5:1 static compression
use 1.6:1 rockers
and it will match that 3.70 rear gear and run on pump gas with a manual trans
youll be gaining a bit more low and mid range, and it will cost you a bit of peak power but it will be a much nicer to drive street/strip engine
your basically forced to use a bit more cam duration to allow the engine to operate effectively in the upper rpm range than would be ideal in an engine thats expected to run at lower rpms but you can still make an engine operate fairly well in both areas with correctly selected parts

 

[dat260]

Thank you grumpy for the reply.
Do I need valve spring girdle (sp?) for float/stability? and how much horsepower would you estimate with this setup? is there a difference between a holley 750 vac sec and a Demon 750? Also is that cam you recommended very lumpy. The reason I ask about the lumpyness is because my car is small (16 feet bumper to bumper) and a lound sounding cam would make my small car look disproporsional.
A loud cam in a 68 charger sounds awsome.
Thanks again,

 

[grumpyvette]

you can use the 1.6:1 ratio rockers with the cam I posted above its almost the same as the one posted a bit earlier but after doing more calculations I feel its going to be a better match, and yes its going to have a rather, noticeable & lumpy idle, and yes using a rocker stud girdle is an excellent idea as it helps stabilize the valve train. but the cam also going to come on strong once the rpms exceed about 3500rpm,, and no its not going to be the ideal street cam, but it will allow the engine to breath once you reach higher rpms, if you want a bit smother idle, all the cams listed will be suggested too be used with a bit higher than 9.5:1 compression, but keep in mind the 377 extra displacement and ability to operate up above 6000rpm requires a bit more duration than your average 350 would require
either cam should allow you to exceed 400hp easily and still have an engine thats both fun to drive and easy to get to rev easily.
everything you do will be a compromise in one or more areas,personally I think either cam choice will be fun to drive once you get the car tunned and the suspension sorted out, but remember these are not going to be engines that loaf along for hours at 1200rpm and run smoothly in stop and go traffic nearly as well as a stock engine but what they will do is allow you to scare yourself if you keep the rpms up and hold the throttle open with your foot firmly on the floor.
the cam below will idle a bit smoother but the cam posted above should produce a bit more power, in either case the difference won,t be great on peak numbers , more in the low and mid rpm torque due to the different LSA more than the slight change in duration

BTW.IF YOUR BUILDING A SBC
http://brodix.com/heads-2/small-block-chevrolet-compatible-heads/ik-series
http://www.jegs.com/i/Brodix/158/1021001/10002/-1

brodix ph# 1-479-394-1075 (ALWAYS VERIFY PART NUMBERS SEVERAL,
TIMES FROM AT LEAST TWO SOURCES, BEFORE ORDERING PARTS)
the brodix rock stud girdle is part # BR-6435 and LIST price is about $230 you can get it for less if you shop carefully
BE AWARE that the I.K. 200 heads were shipped with BOTH 3/8" and 7/16" rocker studs ,
and the poly locks for the 7/16" rocker studs ONLY fit that rocker stud girdle
obviously you need to verify what your heads have before you order the matching rocker stud girdle
Verifying your engines clearances, and rocker geometry, and use of A rocker stud girdle and high quality roller rockers go a long way towards maintaining valve train durability

 

[dat260]

Thank you Grumpy. I have more questions but its late now, I will speak to you again, if you don't mind.
Cheers,