I was going to stick my 70 340 into my 72 challenger, but since I got that 70 challenger, it is going to go in that instead. SO now I have a situation. I wasnt to build a serious stroker. I have a set of x heads and I have a set of marine competition 6 pack carbs, I also have like 3 70 318 blocks. Do I use one of those and stick a 4.00 inch crank in it, or am I better off finding a 360 block, or a new 340 block from mopar? By the way I am looking to clear 500 hp, and 8k rpm.