Y block 312, 292

I know there is a difference between the 312 and 292 crank but what is it?

 

312 crank has 3.44" stroke....292, 272 have 3.30" stroke.

 

312 mains are larger; 2.623 vs. 2.498

 

There is supposed to be a way to tell by looking at the end of the crank but I don't remember what it is.

 

http://www.ford-y-block.com/crankshaftid.htm


Many, (though not all) 312 cranks have a "dot" on the flange notch, as illustrated in Mummert's picture. I owned a verified 312 crank that did not have the dot.

 

I bought 2 motors yesterday that are supposed to be 312's but I'm not sure. Thanks for the help.

 

The only guaranteed way is to check the stroke. Even the block casting won't tell for certain, as the same block was used for some 292s as well.

Not to rain on your parade at all, but if they are indeed 312s, you will want to check the cranks for cracks, and check the block as well for damage in the main webs, especially around the main cap bolt holes...

 

According to the information you gave both motors are 292's

 

One other thing to look at is the main caps. EBU caps are 292, ECZ caps are 312.
Mummerts site is the best place to start trying to figure out what you have. Lots of good info there.

Marc