That should work out fine as is, but you should really find out--just so you know for sure--what that engine is. As I said, if he told you 454, that cant really be so. If it was me, I would have to know, that's how I am. The problem with buying something already built is that you really dont know for sure what you have unless the seller has all the paperwork. If you go to buy parts and build on this engine, you're going to have to know for sure what the bore and stroke is, deck hgt, cam specs, pistons and rods, all the particulars. Im sure he will tell you if he's not hiding anything.