On a 1978 Bronco what is the name of the piece between the Rear-end (Ford 9") and the U-joint on the driveshaft? Is it the pinion flange I am trying to replace it and it is a little hard when you don't know what to ask for? Can I use one off a truck?
Also is the 351M a big block engine?
Thanks
Greg (a.k.a. The Tree)

 

If it's the part that the u-joint fits in, and is held on with a large nut, then yes it's called a pinion flange.

The 351M and 400 are considered to be small blocks. They are based on the 351 Cleveland block.

Good luck with the Bronco. And yes, a pick-up of the same vintage will have the same rear diff parts (Ford 9").

 

Actually, it's a "yoke". The "flange" is a flat disc with threaded holes in it, used from ~'89-up.

 

Engine Description