A different Q on 340 Vs 416

Are these the RPM heads with the .060 cut for piston clearance with out of the block 340 pistons?
get your quench down to the .035-.040 range (note I did not say .030 with the roller cam)
for saturday night build I'd go stroker (also easier to get compression) and keep whatever gears are already in it till you have to change for some reason
the stroker and the 340 will make about the same head dependent top end HP (340 at higher RPM) but the 400 will make more torque below peak HP- where you will driving it most of the time