I had a block sonic checked a few years ago. They wrote on the block so I transferred the numbers to paper.
Mercury marine 330hp 454 casting 10069286 1989
Ed Hale in San Diego did the sonic work. I was planning a 8-71 blown 496 for my car. He said that the numbers were sufficient. See pic #1 thinnest was .139 non thrust and .143 thrust.
I just had a different block done and OMG is it thicker. Pic #2
it is a 1975 casting 364776
It is about double the thickness!
Is there really this much difference in the castings?
Has anyone else had a block sonic checked? Do you have the sheet that you can post?
I thought that the marine block would be better, but.............