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The 440 overbore question

So you're saying the -7 on the end of the casting number in this picture means the cores were replaced 7 times. Interesting. I hadn't heard that before. Thanks!

View attachment 572077

Yes, at least I was told/read that many years ago... Rule of thumb was to look for a block with a low dash number. Yes, a sonic check is the true test. I used to get asked to sonic check, and now that I got one, not asked once, lol....
I’ve sonic tested a bunch of ‘em over the years. There are no thin wall castings per se, but there’s a lot of variation in the cylinder wall thickness and some are afflicted by core shift with thick walls being opposed by thin ones. We had some guys bring in an old 440 race engine for a freshening. We pulled it apart and it was being run at 4.400 bore with a short fill in it.
Welcome to FBBO

some good advice here
Thank you, everyone, for all the advice I'll post pictures when the block is done.
Everybodys advice is good, i wouldn't put any large money into machine work on a block without sonic checking it first.