Ron
Enthusiast
A while back I bought a set of Jeff Morys GENII OEM Stage III cylinder heads for my 1996 GTS from Steve Viperair. They were used but refurbished by Jeff to be 'like new," which in fact they look to be. Believing in the Reagan doctrine, "trust by verify," I took them to a local shop (where they machine drag racing heads and dual quad tunnel ram intakes out of billet aluminum) to be checked, flow tested and cc'd. Turns out they are in fact in perfect shape, flow great and all Steve said they were but for one thing, chamber volume. The chambers are 77 cc's not the claimed .030 cut 75cc's.
My questions are;
What would my compression ratio be on a stock GENII engine with these 77cc chambered heads and/or what is the specific formula for calculation of same for a GENII?
and
Is it worth shaving them a bit more to up that CR number, and if so what would be the optimum compression ratio for a 98% street driven, normal pump fueled and occasionally tracked, stock 708 cammed GTS with no mods but Crower shaft mounted 1.7 rockers? Stock intake, exhaust, ECM, cats, etc. Know full well that this approach doesn't come close to taking full advantage of the head's capabilities, but it fits my wallet, reliability & drivability preferences, at least for the moment.
Thank you
My questions are;
What would my compression ratio be on a stock GENII engine with these 77cc chambered heads and/or what is the specific formula for calculation of same for a GENII?
and
Is it worth shaving them a bit more to up that CR number, and if so what would be the optimum compression ratio for a 98% street driven, normal pump fueled and occasionally tracked, stock 708 cammed GTS with no mods but Crower shaft mounted 1.7 rockers? Stock intake, exhaust, ECM, cats, etc. Know full well that this approach doesn't come close to taking full advantage of the head's capabilities, but it fits my wallet, reliability & drivability preferences, at least for the moment.
Thank you
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