engine bearings SBC
 

Would someone tell me the difference between the Clevite MS909P Main bearing and the MB2508P Main Bearing.

The MS909P is a standard LJ350 main bearing. The MB2508 appears to have a .020 reduced width on the rear main, probably for a block that spun a rear main and required repair.

Thank you very much. I quess it would be smart to replace it with what I took out correct?

I would...unless of coarse what you took out wasn't working. :D

This site gives you measurements for that bearing. Measure your block and old bearing.
http://www.enginetechcatalog.com/Int...Set%20-%20Main

Thank You !![/b]