On all of our race 292's, we tried to make sure the minimum wall thickness was at least .150 on the thrust side for any overbore. Sometimes you will find that even at .030, you will be thinner than that. On street engines we found that a thickness of .125 was a fairly safe cylinder wall thickness for the finished bore size to use as a guideline. Quite often we had to offset bore a block to be able to use it because of the core shift problems that can occur when the blocks are cast. Sleeving a cylinder is an alternative,but only if you plan to bore the engine, because it distorts the adjoining cylinder too much to allow them to stay where they are without boring them back to a round and straight shape. We found that the Mexican blocks were always much thicker in the cylinders than the US blocks were, as were some Canadian blocks. So if you have a Mexican or Canadian block, that could be a big plus for you.
