Need to have it sonic checked, but not uncommon to go up to .100 over.

 

My 512 427 block in bored .070.
James

 

.070 easy. .100 have it sonic checked. That's one of the best and thickest/strongest big blocks of all time.

 

Agree with Tom. 70 is no problem with that block.

 

We cannot "assume" that whoever bored it to .060 bored it on cente. Meaning what if it was bored off to one side or another. Sonic check as suggested.

 

You are only taking off .005 per side. Bore it, no use to waste money on a sonic check for that amount.

 

I have sonic tested 454 blocks that would not go .060 over. Its always one cylinder that makes most of those blocks fail.

 

When you speak of boring from a worn .060 over to .070, isn't that a power honing Job?

 

Some shops that don't have good hones will bore them.

 

A 0.010" increase is only 0.005" per side, about the thickness of a piece of copy paper. Depending on how deep the marks are, 070 overbore might not get rid of the marks.