Use a table ban saw to hack off the 340 piston crown .

Dan the man said
Why not just buy flattop pistons to begin with? Machine shops have the proper equipment to do things like this. Are going to balance the pistons yourself?

dan, you're late to the party. go back to the 1st page and read the whole wonderful, terrible, no good, very bad idea from the beginning.

also, he doesn't believe in paying machine shops. so, go in knowing that.