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

How's this... Best offer so far...
If you scrounge up the money to ship your pistons to me & back to you I'll mill them for free...

Just figure out an accurate number that you need taken off... If you prefer I have a band saw too.....


View attachment 1716092750
Looks like you're all set, just grab the belt sander with 16 grit.
Remember just hold it flat and level and move it slowly, let the paper do the work.