Mine was stock and it pulled the rist pin out of the piston and bent the rod..I am now working on this combo +5 Hot Rod crank, 105mm CP Piston, stage 3 Hot Cam.. The piston is 11:1 but we will adjust it to 12:1.... The head is P&P.. Please let us know how your's go's and I will post on mine... oh and I am looking at 68 to 70rwhp. So far I have about $900 in it..