View Full Version : Question about chevy 400 small block


jarednut4ever
03-16-2006, 06:15 PM
We are building a 400 small block. We had it bored .40 over, flat top pistons full floating. 10.5 compression, heads are stock 194 intake 150 exhaust. 292 comp cam, 501 lift, roller rocker arms, performer RPM intake, performer carb, 1-5/8 long tube headers, electric fans.

One question is how much power will this motor make?

Second question is what is a safe rpm limit on this 400 small block? We
have ARP bolts on the rods. Let me know guys. Thanks, Jared

TJSZ
03-16-2006, 06:46 PM
Your heads are going to rob most of your power. You probably will need 2.02 and 1.60 valves and some porting to see better #'s. 400 in stock crank and rod configuration are not high reving monsters. My guess is the 6K range at most.
Make sure the heads you are going to run have the air vent between cylinders drilled if they are non 400 heads. Since the 400 does not have water passages between cylinders, you heads must have those vent holes. You may already know, but just in case.

jarednut4ever
03-16-2006, 07:32 PM
My my heads have the steam holes already. I know that the heads are not the best but what kind of power do you think it will make anyways.

billsbird
03-16-2006, 10:57 PM
Hey Jared, I don't know what power you'll make but I can tell you what my motor used to make. I had {actually still have but it's apart} a 400 bored .060 over {don't go .060 over like I did}, with stock crank, rods, TRW pistons {compression around 9:75 to 1}, Crane cam with 224/234 @ .050, lift around .490 {but it had 1:6 rockers so it'd be more lift}, Performer RPM manafold, 850 Double pumper, AFR 195 heads {76 cc, 2.05 intakes, 1.625 exhaust, don't remeber the header size it was dyno'ed with {either 1 5/8 or 1 3/4"}. It put out 499 Ft. Pounds @4000 & 438 HP @ 5250 on a flywheel dyno. Guy who built the motor said it'd put out more HP & probably not even lose any TQ. with a bigger cam. It didn't wind very far at all, like 5500 RPM Max.... It was a real Tq. monster {well, relitive to everything else, a Tq. monster}. They aren't high reving motors. Remember your power is going to be in your Heads. If you put money anywhere, put it there..... hope this helps ya. Bill

bigml406
03-17-2006, 12:06 AM
if you upgrade the rods and crank you can turn higher rpm's.i shift mine at 7000

TJSZ
03-17-2006, 11:11 AM
I will say that I had a similair setup years back with a smaller cam, I believe it was comparable to the old comp cam 268. I did have 350 rods with the shorter deck pistons. Absolute torque monster.
In a 3800 pound car it would run 12.5s untuned all day if I could get traction and keep it from vapor locking.

8a8mfh
03-17-2006, 07:26 PM
I had the same exact engine, every part you list I had except I had a .030 over 400 with a holley 750. With a 4 speed manual it would run a 3400 pound car at 12.8 in the 1/4.
Had a stock bottom end with cast pistons and ARP rod bolts. A few times street driving my friends would tell me I hit 7500 rpm a lot, I never look at the tach, just shift by feel.

SeeYaSucker
03-17-2006, 07:56 PM
I had a destroked 400 (377) with about the same set up, had the 292H cam with 10.1:1 Comp. made 324Hp at the wheels through a Th350 and 12 bolt in a 79 Z28.