I have a standard bore pontiac 230 block that the thinnest part sonic checked at .238" (and a .030 over 250 block .060" thinner! Both engines use the same STD bore), so if the 230 was bored .125" over would still have .113" on the thinnest part, which was the front of cylinder #1 (on both blocks). Maybe Pontiac's had a few thick runs?
You actually are going to be in better shape than you think. When you bore the cylinders, only 1/2 of the .030,.060 or .125 comes out of each side of the cylinder walls. So at .125 over you will only be loosing .0625 from the wall thickness and be thicker than thought.
