Back to regular programming - 351stang67
, I don't know what you had on your engine before or what else you're changing. Although quench value is going away around .050-.060", if you didn't have det before, and you are also going from open chamber to closed chamber, you may be fine. Right is right, but you may want to try a standard set of composite gaskets and see where that gets you if the budget is tight right now. If you get det before reaching MTBT (Minimum Timing for Best Torque), there are cheap work-arounds like richer mixtures, cam retard, re-curved ignition timing, etc., but those can cost a bit of power. Better fixes would be different cam timing, improving quench, better fuel, etc. Your call.
Yes, I am going from open chamber 2V heads to Aussie heads. The heads have been ported and the chambers are now around 65cc now before having them milled/surfaced. (just cc'd them last night). They have been fitted with 2.19/1.71 valves and I am very impressed with how well they have been done. The chambers are usually small on these Aussie heads, but the ports and chambers have been blended very well. That's the reason the chambers are now 65cc vs. the stock 59-62cc.
I am also changing the cam to a Lunati VooDoo 62504. I was going with either the 62503 or 62504, but my setup is more in tune with the 62504 (especially compression). This is an occasional weekender type car & project so just a little more cam with the right setup should make for a fun ride.
The main reason I am avoiding any block work is the bottom end was redone years back and has very few miles on it (maybe 250 at the most). It has TRW flat tops, and you can still see the cross hatch pattern in the cylinders. So I hate to tear into it for that reason and the fact that I do not want to pull it from the car unless absolutely necessary.
I am thinking if I could get a head gasket down in the .027 range I could have a more effective quench, and I could keep my compression around 10.5:1 which the 62504 cam needs. If I were to have compression closer to 10.2:1 and go with the 62503 cam, I am worried I may be at more risk of detonation due to the smaller cam and less effective quench.
This is the basic dilemma I am at and trying to decide my direction.
The Cometic C5871-027 could get me to my target, but I am concerned over getting a proper seal with a MLS gasket.
It looks like the thinnest composite head gasket I've seen is .038 ?
By the way, I plan on running 92 octane pump gas, and no more than the car will be driven I can add some octane booster also.