Originally Posted By gregsdart
The main bearing journals are smaller on the B cranks. RBs are 2.750, Bs are 2.675? An RB crank will have a circumference of 8.639 inch, or 8 5/8 plus a touch.


Originally Posted By DoctorDiff
You don't have to measure anything.

If the rear main bearing journal is almost the same diameter as the rear main seal journal, you have an RB crank.

If the main bearing journal is noticeably smaller, you have a B crank.


Thank you both!!

that is what i wanted to know.
...and who keeps a tape measure in their pocket at all times??