My '72 455 main bearings have a 'B' on them. The factory service manual says that means they are 0.0010" bearings. I assume this means undersize? Was that on the diameter or the radius? Did the factory just use the different sizes to compensate for slight differnces in crank main journal machining diameters, or does that mean it was rebuilt at some point? Thanks. Tom

 

Yes the bearings were selective from the factory, as were the pistons.
my service manual dosent say if it's over sized or under sized either.

jason

 

by 10 thou if B ,5 = A , 15= C

 

^^^^^ CORRECTION a= 0.5 thou , b = 1 thou , c=1.5 thou