I was wondering if anyone could tell me if a model b crank and cam shaft will fit into a model a block? the model b block is junk and i have good model a engines to put crank and cam into. i thought i read a post on this but i cant find it now.i know that a model b distributer will work on a model a but what other parts from a b will work ? if i can use the crank and cam, what pistons and rods do i have to use ? thanks
B cam will work in A block, B crank will not work without machine work since the B crank (and rod) journals are bigger than A.
Flatty The B crank will fit into the A block after the mains are turned to the A crank dimensions. You must use the B rods unless you want to go to the expense of having the rod journals reground to the A dimensions. If you use the B rods, you will need to get new (smaller) rod nuts to clear the block pan rail. As I recall, a stock Ford flathead nut or a small block chevy nut will work. You're going to a lot of work, unless you have a good "counterbalanced" B (or C) crank. Jim
Model A main bearings are 1 5/8" dia and the main bolts are 2 1/2" on center. Model B main bearings are 2" dia and the main bolts are 2 7/8" on center. The main bolts on an A block are too close together to be able to bore the block big enough to use the B crank with the 2" mains. You would have to turn down the main journals of the B crank to use it in the A block. You can still use the B rods in the A block. but you will have to either use the B pan or modify the A pan to clear the rods. They will clear the block with out modification. If you look at your stock pan you will see that there is 4 bulges in each side of the pan to clear the rods. A pans do not have this. You can find B blocks for $250 - $500. In my book that would be the better way to go. The machine work required to make the B crank fit in an A block will cost about as much. My $0.02 .
The Jalopy Journal
