Did the bottom end and replaced the piston in this motor. It starts and runs like a champ but when it gets hot there is a knock at idle. It disappears when I give it gas. Its a wiseco piston. The cylinder has no marking of A,b,c,or d neither did the piston that came out. I know that year came with 4 different size pistons. I'm assuming the piston I got in the kit was SIze a and that the knocking when its hot is from the piston being too small. Any feedback would be greatly appreciated.