Pistons used to be available in what's called "semi-finished" size. They were then diameter-turned and cam ground to whatever size the engine builder needed. However- - - - -even if it were possible to find semi-finished pistons these days, those paper thin cylinder walls would cause an instant overheat situation, and piston ring life would be extremely short. Either sleeve all the cylinders back to standard bore and start over, or find another block. Is there some overpowering reason (like maybe an engine number that matches the title) to keep whittling on a worn out block? Unless you happen to have your own machine shop (I do) six sleeves and the labor charge to install them at today's prices will cost close to a thousand dollars.
Once you get custom pistons made in a too-big oversize, where would you start looking for suitable size rings to fit them?
Jerry
