1968 ( 318 ) main bearings - Input requested

SGBARRACUDA said
Chris the difference in SB and BB in 74 was the Width of the thrust bearings.
Main bearings for 318's changed in 1974 to a different thrust width, pre 74 used (for example) Clevite MS-540p with a max thrust diameter of 3.374 inch, then 74 on used Clevite MS-1344p with a max thrust diameter of 3.530 inch.

Thanks Roy - I used the 68 block I bought from u and it cleaned up nicely # I guess I could have used the 74 model and not really had this issue but I wanted to have the oldest one in my car first , If I ever bust it then the 1970 block u sold me will go in next .