1994 k1500 383 tbi

[Taz069]

Welpers here is the awaited up date. Stroker out of prison and home. My question was answered by another customer picking up his 383. Note stage 2 cam as mine hydrolic roller like .520 lift for get the exhaust with 110 lobe separation. Using stock heads good for 300 h.p. ,stock intake, stock stamped rocker arms, and cast parts. He was quoted. 325+/- h.p. possibly around 350+/- torque. Now mine was next in line to be loaded. Dude goes well how about this 383"mine" Mr.Pilcher said 450+/- h.p. and 475+/- torque. Dude looking concerned asked why? Per Mr. Pilcher yours was built the way YOU WANTED. His"mine" was built right With a stage 1 cam. Included is the cost break down. And I have no clue on the balance chart? Maybe somebody knows Now more parts and pieces

 

[L31MaxExpress]

I think he seriously under estimated the torque of the other engine. You could build an 8.5:1 383 with 76cc smog heads and the stock camshaft and it would hard to detune it enough to make less than 400 ft/lbs. The stock 8:1 Goodwrench smogger 350 replacement has made ~350 ft/lbs time and time again when dyno tested with headers, edelbrock intake and a Q-Jet. The HT383 makes nearly 450 TQ @ 3,000 rpm with 9:1 compression, stock vortecs and its tiny 196 @ 0.050 roller cam. With 10:1 compression, good heads and a decent roller cam I would expect 500+ TQ.

 

[Taz069]

I think he seriously under estimated the torque of the other engine. You could build an 8.5:1 383 with 76cc smog heads and the stock camshaft and it would hard to detune it enough to make less than 400 ft/lbs. The stock 8:1 Goodwrench smogger 350 replacement has made ~350 ft/lbs time and time again when dyno tested with headers, edelbrock intake and a Q-Jet. The HT383 makes nearly 450 TQ @ 3,000 rpm with 9:1 compression, stock vortecs and its tiny 196 @ 0.050 roller cam. With 10:1 compression, good heads and a decent roller cam I would expect 500+ TQ.

@L31MaxExpress they told me after he left the stock heads he had were only good up to 300 h.p. and no porting and polishing done.

 

[Taz069]

@L31MaxExpress they told me after he left the stock heads he had were only good up to 300 h.p. and no porting and polishing done.

These also weren't vortec heads.

 

[L31MaxExpress]

@L31MaxExpress they told me after he left the stock heads he had were only good up to 300 h.p. and no porting and polishing done.

I cannot think of a single small block 350 head casting that cannot make 350 hp. Also torque is more a function of compression, cam timing and displacement than head flow. I built a 9:1 406 once with stock TBI heads the mildest "RV" cam out there and it still made 500+ ft/lbs and over 350 hp. It was done at 4,500 rpm but it had diesel like torque. Was perfect for the application though since it was moving around a 12,000 lbs RV towing a 5,000 lbs boat.

 

[Taz069]

I cannot think of a single small block 350 head casting that cannot make 350 hp. Also torque is more a function of compression, cam timing and displacement than head flow. I built a 9:1 406 once with stock TBI heads the mildest "RV" cam out there and it still made 500+ ft/lbs and over 350 hp. It was done at 4,500 rpm but it had diesel like torque. Was perfect for the application though since it was moving around a 12,000 lbs RV towing a 5,000 lbs boat.

Sir I wish I had the proper answer for the #'s you have put forth. All I know is what the folks at the shop told me. A 300 h.p. head won't make 400 h.p. not proper valve size? Intake and exhaust? No porting and polishing. Not the proper intake,"stock" as well as the intake stock? Flow factors and all. No matter what size cam you throw at it? If it doesn't flow?? Sorry I don't have his as built sheet and more specifics.

 

[L31MaxExpress]

Sir I wish I had the proper answer for the #'s you have put forth. All I know is what the folks at the shop told me. A 300 h.p. head won't make 400 h.p. not proper valve size? Intake and exhaust? No porting and polishing. Not the proper intake,"stock" as well as the intake stock? Flow factors and all. No matter what size cam you throw at it? If it doesn't flow?? Sorry I don't have his as built sheet and more specifics.

My point is there is no such thing as a "300 hp" head or a "400 hp" head. Flow does not matter all that much for torque either.

 

[Taz069]

My point is there is no such thing as a "300 hp" head or a "400 hp" head. Flow does not matter all that much for torque either.

Welp sir if you have a cruddy head that doesn't flow 180cfm's VRS one that flows over 300 cfm? Might be a choking point? Will let the elders chime in. Just know what my builder told me. My .02 if the engine cannot breath than you restrict the motors true abilities. Many books out there in regards to good and bad heads. And not many recommend stock intakes for power??

 

[Taz069]

Here's a picture they sent that I didn't have.

 

[Erik the Awful]

L31MaxExpress' point was that any Chevy head can make 350 hp. I think your engine builder was talking in generalities when he said "300 hp head".

As for the rest of the conversation, it's all the Theory of Constraints. When it comes to low end torque, the head matters less because you're not maxing the flow out. At a high rpm the flow through your heads is the constraint, but at a lower rpm the heads can flow plenty and the camshaft is the constraint. However, if you maximize the camshaft for low rpm torque the camshaft can become the constraint at high rpm.