Turn a small drill press into a Bore/ Hone. Bolt it to the top of your engine block & do your own machining .

Everybody told you the band saw piston hack wouldn't work, and it didn't. Maybe you should stop being so stubborn. This reminds me of my old boss trying to build a never-done-before device to spin at 20,000+ RPM. Instead of spending the initial money to hire a seasoned engineer with high-speed rotating machinery experience he threw hundreds of thousands of dollars in the trash making a bunch of 500-lb paperweights with a fab shop that had never built something that moves. As far as I know he's still trying because having 20+ years experience managing junior engineers in the military means he knows how to make something like that work. Riiight.

Don't be like that guy.