hp/tq and E.T for a 3400 lb car with a forged 383 4340 crank rods and pistons, with iron heads that flow around 320cfm at .600 with a custom ground nitrous cam with .630 lift on the intake .621 exhaust victor jr. intake and a holley 750 d.p. with 11.5 c.r. thanks

 

tranny/gears/suspension/tires/driver skill?

 

whats the ratio on the rockers that will make or break 20 hp also step headers or equal full length or shorty my estimate with out the n20 would probably be around 400 at the crank just guessin but with that ratio and the n20 you better be putting some high test fuel or go leaded
just my
jon

 

1.6 rockers, leafs with slide a-link bars, 3:73s.,th350, E.T drags, good, similar motor with same heads/cam with 150 shot went 9.3

 

320 cfm at .600 lift? What kind of heads are these? I don't have anything over 300 in all of my list of head flow numbers.

 

I was going to ask the same thing. My brodix are fully ported and only flow 305 on the intake. Maybe hes talking 18 degree heads.

 

they are fully ported and polished world product heads, done by a local shop(jacksonville) and flowed 315cfm at .600

 

i would guess around 450 hp if the heads are what they are said to be. and torque should be well over 500. correct me if i am wrong but isnt .630 and .621 lift just a little much for a 383?

 

No, as long as he has as much flow as he says he does. I'm running .616 on intake and .618 on exhaust plus I have 1.6 rockers on intake making it .658. I'm thinking he will have over 500 hp at the crank.

 

turns about 7200 rpm

 

What World Products casting are they? I'm just amazed at the flow your getting and I want to know what kind of heads they are. Obviously the shop put them on a flow bench so you know the numbers. But I'd like to know the original casting.

 

I'm thinking 450-475 at the wheels w/o juice. torque will be ungodly.. maybe around 575.

 

Why do people always assume that 383's will always produce gobs of low end torque? The biggest complaint I have about my 383 is the lack of low end torque. Don't get me wrong, I can definetly and easily give a good smoke show without doing a brake torque, but compared to my old 350 with 4.10s and 10" converter it feels weak.

 

My old 383 made about 500 hp. It had a 400 crank and rods with stock rod bolts. It had stock cast 350 pistons. A good solid cam, ported camel back heads with large valves. Single plane intake and 850 DP carb.

It was enough to push my car into the very high 11's at altitude. It was a lot heavier than it is now. After 2 years of racing and shifting close to 7000 rpm, it finally threw a rod and destroyed the engine. The only thing salvagable was the intake and the head castings. Most of the valves were bent. The complete short block went into the scrap metal bin at work.

If you want to know what a vehicle will run, take it to the track and find out. If you want to know how much power is getting to the wheels, take it to a chassis dyno. Just because an engine has a bunch of fancy high tech parts doesn't mean it will perform as expected. Most good aftermarket parts build no HP (4340 crank etc) but only add to the reliability of the engine. 320 CFM heads on a 383 are overkill unless you plan on spinning the engine to 8000+ rpm or you're going to use a huge blower. My new aluminum heads for my BBC are only 310 CFM however they also have large valves that a SBC head could never fit.

Also, for SBC heads that flow that much you have too little compression and way too little carb to make them work properly. 13:1 compression and a 1050 dominator would be needed.

 

The engine will eventually see a cam with ove.700 lift, thanks for your information stephen, the set-up isn't together yet, have all the parts ready just need time to assemble, i'm just trying to get some est. thanks.

 

The engine will eventually see a cam with ove.700 lift, thanks for your information stephen, the set-up isn't together yet, have all the parts ready just need time to assemble, i'm just trying to get some est. thanks.