I have a 1969 block that needs to be bored over to .060 but my local machine shop says I should get a different block. Now I've heard that the 1969 blocks have thicker cylinder walls and was wondering if the 1969 block can handle running with a 0.060 with little to no issues? I've heard that if they do have issues its usually cooling.

 

I would trust the machine shop and get a new block.

 

Even if you don't have a core shift problem, .060 will allow so much heat to get through the cylinder wall you'll have trouble keeping it cool. If this is something special, see if they can sleeve it. If not, replace it.

 

60 over will work for a short track engine where cooling is not a big deal, but for a driver, it's way to big. I've always stuck with no more than 30 over for a dependable SBF.