Question: I have a crate 383 stroker (360hp/410lbs) on Sealed Hyperutectic Pistons(yields 9.5:1 CP, flat top, 2valve relief); GM Cast Iron heads (Valves: 1.94int/1.5exh)(72cc/170 runners)...Compressed Head Gasket of .041..Standard deck height..Comp Cams Hydraulic Flat tappet .477/.480 lift; 110 lsa; 224/230 dur. @0.50" Advertised Dur. 268/280. I want to run Aluminum Heads (preferable trick flow's, AFR, Dart) with 190 or 195 intake runners & 2.02/1.6 valves. What size Combustion Chamber should I use to keep a CP ratio of nothing greater 10.5. (Street Driven/ Maybe some Track car).....Thanks

 

62-64 cc chambers will give 9.5-9.7 compression. That should be good for the street. 10.5:1 is a little high for street use.

 

10.5:1 isn't high for street use, just have to change the type of gas run in the car. All of the LT1s are 10.5:1 as are the LS1s as well. Just have to run premium in the car instead of regular.

If you want to keep it around 9.5:1 I would get something similar to a set of Vortec heads cc size.

 

what would my power bogie be if I decrease Comb. Chamb(64cc). & increase velocity flow(190-195 runners) vs. keeping same Comb. Chamb size(72cc) and increasing velocity flow(190-195). I will also increase the valve size to 2.02/1.6
Remember the tpe of Cam im using

 

LT1's have reverse flow cooling, which keeps the combustion chamber cooler, and aluminum heads (except for the B-body engines, which I understood were lower compression), which transfers heat more readily. The chamber shape is also superior for handling detonation. Together, about 1 point higher static CR is possible with the LT1 than with Gen I SBC's. Only the Vortec chamber shape translates to higher CR capability on Gen I's (aluminum also if you go with something like Fast Burns).

LS1 heads are also aluminum and have superior chamber design, so nothing there translates to Gen I SBC CR capability.

All that said, you can still live with 10.5:1 on premium with Vortec-style heads, but you'll have to control details such a quench carefully.