Given that everything else about your build screams "torque monster", I think a single plane would be a mistake. You'd give away mid-RPM torque, and you don't have enough cam to make it up, up top where the M1 will shine. An Eddy RPM or the new Mopar high rise dual plane (RPM clone) seem like the natural best choice here. Also, most of the comparisons I've seen would suggest that the RPM isn't giving much away up top anyway.