Another 87 octane/aluminum heads question

Actually dynamic means much more than static in the real world. That is what the engine really sees, not static. And if you like the cam, which is going to be your friend for fuel mileage, then the 308's may be the best change to make. If you are at 8.2 DCR now, it is not going to be too hard to get down into the low-mid 7's to be able to run the lower grade gas.

I'd look once more at the aluminum..... since with that, you gain at least 0.5 point higher in CR with the same resistance to detonation. I would look at the 65 cc Edelbrocks and englarge the chambers some, and thicken the head gasket. With the open chamber and a gasket of at least .051" thick, you are out of the supposed piston-to-head gap range that is more prone to detonation (something like .060 to .080" gap). You can even go larger in gap with Cometic head gaskets.

As for the PCM and the AFR, has the narrowband O2 been replaced? If it ever saw leaded fuel, it could be compromised. If its readings are off, then where the PCM adjust to will be off.

Of course, moving a vehicle-shaped cinder block through the air with 4.10 gears is only gonna be so good on fuel mileage LOL