Reviving this thread as I'm diving back into this engine build.
Turns out the block will need bored after all, which opens up piston options a bit more, but I've got another problem, which is that I think I've been operating with the wrong assumptions in terms of what I can get away with regarding cranking compression.
I've been operating on the assumption that ~180psi is going to be workable on 87 octane with good quench, but it looks like I have been wrong about that. David Vizard says one should be able to get away with 165psi on a tight quench motor with 87.
Unfortunately that presents some real problems. If I want to preserve the .039 quench, and I run the largest dish hyper piston I can find (25cc KB416), that gets me down to 9.04:1 static compression. Sounds great right? Well, I would need a camshaft that closes the intake valve 60* ABDC to get the cranking pressure down to 164psi. That's something in the 252 duration range! That strikes me as a terrible idea for a daily driven pickup truck.
The largest dish I can find at all is 34cc (Icon 9977), but it's 2618 forged which require a lot of piston to wall clearance and will significantly reduce service life, which is important in this application.
Does anyone know of a larger dish cast, hyper, or 4032 forged piston?