Ok so I'm considering buying a big block instead of re-doing a 350. A guy has what he says is a 396 block, the casting numbers are 3999290. Mortec says this is a 68-69 396 or a 70-72 402. Now I know a 402 is a .030 over 396. My question is, if it turns out to be a 402, can I take a 402 out an extra .010 or even take it out another .030?? I'm confident that a 396 block can handle .030 but I don't know if it would be able to handle .060. This would not be a race motor but a nice street motor more for cruising than performance. Thanks for any info you guys can provide.

.060 for either block will be fine

I just went .090 on my '69 396 block =418CI. which is the same as 0.060 on the 402. No problems here.

I've gone .125 before, it can be done with a good casting.