Join Date: Dec 2002
Location: Fairfield, OH, USA
Re: What to do about heads?
Do your "plain jane" heads have 1.94" intake valves or 2.02"? I ask this because some of the aftermarket heads have 2.05" and the 2.02"s are relatively smaller these days. 2.02 would be fine if that's what you have.
I'm running AFR/190 cc on my 302 but I had originally bought these larger heads to put on a 383 or 400 which I'm now wrapping up. The little 302's don't require a whole lot of intake runner volume to make them run. If you plan on building something up in the future that would necessitate the 200 cc heads, I'd get them, otherwise, I think your heads would work good with 2.02" valves, but then you have to look at the cost of increasing the valve size because that's money that could be applied to your new heads that would already have the 2.02s in them.
Are you at 10:1 compression because your heads have 74-76cc combustion chambers or do you not have high compression dome pistons? If you do have dome pistons, you'll need to make sure that the newer combustion chambers have room for your piston domes. Just something to consider with many of todays redesigned chambers. Also, if you're at 10:1 with a 64 cc chamber then you should be fine with cast iron heads with respect to detonation.
1969 Z/28 fathom green X77