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

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.
I did read some of the very beginning of this screwed up idea he has. I can't believe that someone would screw up a set of pistons like he is going to do. Does he even know if he'll have enough thickness left over to keep the piston from coming apart? If he doesn't believe in machine shop work I'm willing to bet that his engine will have some serious vibration issues.