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Old 04-21-2011, 11:04 AM
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big block chevy build help please

ok got a 454 in the garage and a set of stock 781 heads.... would 9.1 compresion and about a 572 lift cam work good (heads are bone stock) and a airgap intake with about a 750 cfm carb..... any input is helpful it is going in a 82 c10 3.42 rear just a weekend driver to have fun with

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Old 04-21-2011, 12:41 PM
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It's the intake closing point that you want to match up with the static compression ratio, not necessarily the lift. An intake closing point of 26 degrees to 35 degrees after bottom dead center @0.050", for instance, should work well with 9.0:1 SCR. Counsel with the tech guy at your favorite cam grinder to arrive at the right cam for your application.

BBC engine builders will usually try to discourage you from using a flat tappet camshaft in a BBC, because of their appetite for eating cams and lifters. Howards makes probably the least expensive, good quality retrofit hydraulic roller on the market. If you are still thinking flat tappet, please read this....
http://www.crankshaftcoalition.com/w...ips_and_tricks
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Old 04-21-2011, 12:49 PM
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A 454 with stock flat top pistons and a set of 781 heads will make 7.8:1 cr. You will need domed pistons to get higher compression.

9:1 cr with a 3.42 gear and a stock to 2400 stall converter will run nicely with a 268H compcam. 400hp/500ftlbs.

I would use a regular rpm intake (not air gap).

750 is a little small but ok for a moderate 454 build.

use full length headers and the proper valve springs in the heads.

I would break the cam in using the strock springs.

set the mains and rods at 0.0015" to 0.00020" and the rear main at 0.0025" to 0.0030".


If you plan to use a bigger cam than a 268H then add more gear, more stall, more compression, and a bigger carb.
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Old 04-21-2011, 03:58 PM
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yeah i am wanting it to sound good its going to be weekend street truck.. i was looking at the lunati 267duration 545 lift cam would i be better to get a set of the jeggs heads 310runnrs with 2.25-1.88 valves? and iwas thinking about getting 9.5 they should come down to around 8.7 with the stock heads right i would like to make 500hp at the wheels. what would it take
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Old 04-21-2011, 04:24 PM
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500 at the wheels will be tough to get. That would take a 600Hp engine. stock 781 heads will not get you there without a lot of porting. I would build a 496 instead and use 300cc+ heads.

You would need at least 10.5:1 cr, after market heads, big roller cam, 3500 rpm stall, 850+ cfm carb, forged and balanced internals, 4.11+ gears, and a limited slip diff to have any hope to use that much power. Your truck will not be very nice to drive around town like that. Good for 1/4 mile blasts only and not very durable.

with 3.42 gears in a truck you will be limited to a 2800 stall, maybe a cam with 280 degrees duration advertised, maybe 400 hp at the wheels with a good set of aftermarket heads. Maybe 435hp with a 496.

Change your gears and stall, then you can add more cam and compression to make more power. It all needs to match.

Hope you plan you use a th400 trans or a well built th350.
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Old 04-30-2011, 10:56 PM
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Stroking a 454 is a good way to get cid and tq but does little for longevity, rpm, and hp. If you want to build an engine that wears prematurely, breaks rods and knocks holes in the block then stroking it is the way to go.
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