i was replacing the oil pan and decided to throw in oil pump. the new pumps have a bigger drive cavity ordered a different one same thing. putting on a rear sump pan this motor was out of a 89 e150 it waas a reman that i installed in it now putting in my55. ever here of different size drives

 

Are you talking about the drive shaft hex size? If so then are you sure you are buying a 5.0 oil pump and not a 5.8 pump? The 5.8 uses a larger drive shaft.

 

well i pulled the dist out of a 93 5.8 and thought i bought a 5.8 reman used the same pan and top end every thing bolted up been running for five years had to replace the dizzy as bent old one shafts were same size and both engines say 5.8 on efi intake

 

well what ya know 5.0 block that stinks

 

I'm not sue from your posts what motor you are working on, are you saying you thought you had a 5.8 block but it's now looking like a 5.0?

 

yes its a 5.0

 

bummer man, just an fyi a 5.8 dizzy and upper/lower efi intakes are not interchangable. neither is the oil pump so you have discovered.

hope the rest of the build goes smooth.