I just checked 4 of 7 blocks I have. Two of the ones I checked were Two Bolt Mains, two were 4 Bolt Mains. All four of the ones I checked were Standard Bore. Let me know if you are interested. I am just outside of Charlotte, NC. You can email me at, [email protected]
or call. Home is, 704-867-7566 cell is, 704-516-8033. Thanks, Mike.