Time for new engine

I have bored a few blocks to .060. It's still considered a std oversize. Year of block means nothing. Some are good, some arent. The only big difference really is the material. The earlier iron is not as good as post '72, which is generally when the "thinwall castings" came out. (maybe it was '73..Dont recall...) A lot depends on the shop too. If a boring bar is used, it can only index off the center of the exisiting bore. The factory machining we are all aware of, as far as accuracy and quality go...If the shop used a BHJ fixture, or anything similar, than bore centers can be corrected. If they are bored in the "right" spot on a block with bad coer shift, you can have poroaity leading to your problems. If possible, dont go +.060 for anything. If you do have to, either have the sonic check done, or roll the dice. For real performance builds, especially with longer than stock stroke, and shorter than stock pistons, I try to only use .030 over. I havent had any issues with .060 over engines...but I'm sure it's a matter of time.