View Single Post
Old 06-14-2013, 08:51 AM   #2
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 6,159
Default Re: Model A and B engines

One version of "B" crank looks like a thicker "A" crank, thr other 2 versions have counterweights, one is forged one piece, the other is shrunk on rings, the shrunk on rings are better from a balance standpoint, but worse for grinding rod journals because they have to be moved to grind them

cylinder bore --std A, and B, 3.875" --the stroke is the same for A, and B
A rod 1.498 --main 1.623
B rod 1.874 --main 1.998

The "B" oil pump has a little more flow and works in the A
The B cam is a better cam (if not too worn) and works in the A
B engine blocks like to crack at the exhaust valve seats more so than A blocks
both engines use the same valves and pistons
Kurt in NJ is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)