a 420 sbc combo with potential

grumpyvette

grumpyvette

Administrator
Staff member
210cc AFR heads
http://www.airflowresearch.com/index.php?cPath=24_33

IF YOU HAVE A SET OF REALLY DEEP POCKETS
http://www.speierracingheads.com/SRH2.50.htm

3.875" stroke x 4.155" bore
http://www.summitracing.com/parts/CPI-SAM14A-MG/

block
http://www.summitracing.com/parts/DRT-31161211/

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

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

rockers
http://www.summitracing.com/parts/CCA-1805-16/

oil pan
http://www.summitracing.com/parts/SUM-121001/

crane 119651 cam
http://www.cranecams.com/product/cart.p ... il&p=24187

420sbc.jpg
 
Just to be clear - it is the longer stroke that adds the 20 CI, correct. Plus the block needs to be clearanced for rods to clear...
 
DorianL said:
Just to be clear - it is the longer stroke that adds the 20 CI, correct. Plus the block needs to be clearanced for rods to clear...
Click to expand...


true, and the difference between this and a similar 406 cubic inch displacement would not be all that great if everything but the slight increase in stroke remained consistent in the build, Id also point out that a supercharger like your currently using would potentially easily exceed those hp/tq numbers on a similar build with lower static compression and a different cam meant to help the supercharger
 
Hmmmm, a centrifugal on a 420 CID... now there's an idea... with -36cc pistons.

Can't be too many of those on the street...
 
you can easily increase your current hp/tq with a different cam,having about a 240/250 duration ,but your already pushing the limits on a stock block, rotating assembly and lube system, and a higher stall converter and lower 4.11:1 rear gear ratio, and DART block would most likely be mandatory , and while you'll gain noticeable peak hp you'll hurt drivability on the street

like this
http://www.cranecams.com/product/cart.p ... il&p=24184

but before Id look at that option Id at least consider going BIG BLOCK, because a 454-540 BIG BLOCK with a supercharger correctly built would have a great deal more strength,durability and potential power

YES , ITS TRUE,THIS HOBBYS A BOTTOMLESS MONEY PIT
 
Hmmm, I was thinking keeping my cam - I really like its streetability. Dropping compression and slightly upticking boost.

Throwing 20 CID in the mix... Hmmm....
 
Oh, now this is good... a very good contact. I could use a short block like one of these... Save my nickels and dimes and have it shipped here. This looks good.
 
Hmmmm Grumpy, can you run a dyno simulation for me with these CID + a little more boost on -36cc pistons?
 
420sc.jpg


keep in mind that I don,t have all the specs to use on your engine, so this, is probably just a good trend indicator as to the potential results,but adding a supercharger to the original combo and retarding the crane 119651 cam 4 degrees and lower the compression with those 36cc dish pistons results in this wild software induced guess at the results
 
this is what I am dynoing at now with about 7 psi and stock pistons -22cc. Would the 20 - 30 CID make much of a difference? I am thinking A Ohio block with extra cc, CID and 10 PSI.
 
the extra increased displacement, combustion chamber volume and boost pressure should very easily produce a noticeable improvement in your power level and theres zero question the block will be far stronger, at 10 psi vs 7 psi and with the extra displacement Id be looking for a minimum of an extra 10-15% in power increases
 
Yes, THANKS, this is kinda where I am headed. A solid reliable +/-700 on tap.

That trans is supposed to take up to 750HP/TQ. Yeah well ;) only one way to find out :D
 
Basic specs
420 cu in, 10.5 compression 91 octane pump fuel
AFR 235 heads
Super Vic ported by Chad Speier
HVH Super Sucker
ProSystems HP1000 86/97 w/pwr valve in front
Custom Bullet 261/267 .430/.430 - 108/104
T&D 1.7/1.5 gross lift .731/.645
Exhaust 1 3/4-1 7/8 step, 3.5" merge to 6" exhaust


Dart little M
Comp Star crank/rods
SRP Pro pistons 10.65/1
AFR 235cc
SR 261/267 @ .050 .731in./.645ex
Isky EZ rolls
T&D shafts
Super Vic. worked by Chad Speier
Pro systems HP1000

Jim_Barnett_Power344.jpg


Jim_Barnett_graph357.jpg


Jim_Barnett_conditions355.jpg


Jim_Barnett_air_fuel351.jpg
 
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