225 /6 at 250HP?

slant six will need help to get 250 horse ...At the very least a 4 barrel manifold or turbo......easier to put a 360 / 727 and a 3.23 gear should get you where you want to be...just use Shumacher coversion motor mounts from /6 to 360.....Lots of EFI companies out there for SBM....Or just go with a carb