Engine build question


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12:37 PM
Oct 25, 2011
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Aurora, CO
I just built a 383. Same pistons, 906 heads, felpro gasket. Pistons 10 thou in the hole. Came out to 8.8 to 1. Comp xe268, 2.14 181 valves, pocket ported. On the dyno it wanted 38 degrees and made 380 hp. That cranking compression doest sound right at all.

Mine had the deck and heads cut, but pistons were still -0.005" below deck. The 906 heads were milled (I think 0.040"), but I used the Fel-Pro 0.039" gasket.
Compression should have been around 9.28:1 as mentioned above.
Had the Crower Compu-Pro Camn#32242 271/284 advertised, 220/230 @ 0.050" duration, 112 lsa, 0.486"/0.494" lift. Built that engine is 1989.
The heads were rebuilt with stock sized valves, hardened exhaust seats and mildly ported.
I ran it with a stock converter, which was OK, but the performance would have been better with a higher stall converter.
I tried the Weiand Stealth dual plane intake, and the Weiand X-Celerator. Back in '89 there was no performer RPM which would have been a better match?
My engine liked 38-degrees total timing also.
Was running with the HP manifolds and a Carter 750 carb. I admit, the carb need tuning work back then.
As I recall above 2,500 RPM the engine pulled pretty good to 6,000 RPM, but I was never impressed with that engine.
I feel like with a stock converter, a smaller cam would have really helped torque and made a better daily driver.
On the other hand, if I was going to use a higher stall converter anyway, then I could have used a larger cam to have better RPM power.
If I did it today, building for daily driver use, I would use the kb pistons with valve reliefs, Edelbrock 75cc E-Street heads, the Hughes Engines SER1620BL-12 cam 216/220 @ 0.050" duration, 0.495"/0.503" lift, and the performer RPM intake. Then likely run a Holley Sniper EFI with timing control to make tuning alot easier, with better start up, and warm up.

glen e gates

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2:37 PM
Apr 10, 2021
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lehigh acres Fl. 33972
Ive been following threads about compression ratios, CC combustion chambers and such and I wanted to get some advice
So I have a 69 383 engine in my car. The heads are from a stock 2 barrel single exhaust 383
They were redone with hardened ex seats, I think some or all new valves, just a basic stock head.
The short block was bored 30 over, decked and balanced, rods were checked and all good bearings and parts
The pistons are Speed pro L-2315 flat top with no valve reliefs
CAm is Comp cam part # 21-223-4. lift .477intake. exhaust .480.
duration 224 intake 230 exhaust
I have a Weiand dual plane manifold and Edlebrook 650 carb and factory HI po exhaust manifolds
I have a stock distributor recurved and rebuilt by our own Ray Halifax
The engine develops 14 to maybe 15 inches vacuum. The needle on gage vibrates slightly
The idle could be better but has no hesitation.
It was pinging and I have about 32 degrees total advance
Since I converted it over to a 4 speed I haven't heard any pinging
Car has a 3:55 sure grip
Compression is if I recall around 180- 190
My question is about the heads. Are there heads reducing HP and would it be advisable to change the heads
While im not racing this car, the performance with the 727 ( stock) was a little disappointing.
Any thoughts are appreciated