318 to 390 stroker

From how you describe the potential uses, then it seems clear that you want a bigger cam and that leads to a higher compression ratio to avoid the low RPM range from getting too soft and being 'completely ridiculous'.

The stroke is helping the low RPM end, but IMHO, might as well select parts based on solid principles. And stroking tends to limit high RPM range, so IMHO you shouldn't sactifice a lot of the low RPM range, like you could more easily get away with in a higher revving, shorter stroke motor.

I'll let others step in and comment on the flow of those heads in a 4" stoker application, which are gonna be the main source of top end RPM limitations. Once there is a handle on that, then the lower RPM range ought to be set based on having a decently wide RPM range, and that will drive cam selection, which will finally drive the static CR selection. Clear as mud huh? LOL

Is the plan to use pump fuel?