Originally Posted by tony1947
Ok,I got for 10$ a rebuilt V8 ford flathead crankshaft,the tag says its for a 46 to 48 ford .I would like to use it in my 52 block. First how do I id it as a 46-48 crank? It does have large plug holes like a Mercury 4" crank. 2nd can I use a 46 crank on a 52 block? I think there is a change with the distrabutor that may have changed it. HELP! tony
Journal sizes are the same as your '52 block, so it will fit in there. As you noted the distributor changed in several ways. 46-48 turned directly on the end of the crank where the 48-53 is on a stalk and is gear driven off the cam.
If I remember right you can change the cam gear for the later one from the 52 because they both bolt on - they run opposite directions. Only thing I'm not sure about is overall length of the crank snout in the 52 application - it might be too long. A quick check should tell you.
46-48 merc and ford cranks are the same. If it's a later 49-53 merc crank the counterweights will measure about 6" across - fords are much smaller.