Help on 408 build

I’m not going to argue with anyone about whether or not you might be able to come up with a specific combination of parts that will yield marginal operation with 93 octane gas and 11.4scr.

It’s absolutely not the path I would take for this application.

I would be shooting for low-10’s scr, and under 8:1 dcr, and be able to easily run a cam that is “right” for the application, rather than one that’s part of a band aid solution that isn’t exactly what the OP had in mind when he built the motor.

I don’t think you can really get where he wants to be without a piston change.

If I were the “project engineer”, it would get a piston change(Icon IC745’s, or any other quality forged 20cc inverted dome piston)....... and budget permitting, aluminum heads too.
I’d get the short block situation sorted out first....... you can always swap the heads in the car at a later date as the budget allows........ but “fix” the short block right the first time around.

Swapping the current pistons to something like an Icon IC745, and leaving everything else as is would put the scr at about 9.7:1.
Swapping to some new aluminum heads milled to 60cc would put you right at that 10:1 sweet spot.

Do it right........ or you’ll end up doing it over.