The truck is a '75 F-250 4x4 FE with a auto and divorced transfer case.

The little "ear" where it bolts to the block on the drivers side of the bell housing on my c6 is broken and I was wondering what c6's I can use for a replacement. There are several ones from 2 wheel drives and cars here locally.

 

As long as the locating pin hole isn't broken out it won't make any difference if a bolt hole is broken. You can run it with no problem with 5 bolts. To answer the ? any FE C6 case can be used if you want to replace it.