15 psi basically doubles NA HP, 400 NA HP 383 is pretty easy to do. Can the block and crank handle the power? I'm inclined to think so, others would be better able to judge that.
So, yes if it is 400hp lets say, or even 350, then it gets me 700-800hp in theory. 15psi is still in the GR45 category even. Now, can the stock short block handle that for several minutes???
