My question is, Are all the internal parts the same I know some of the blocks are shorter,
but is the crank,rods, cam (other than lobes) length.

The 2.5 engine is in so many different things (i.e. Mail Trucks, Boats), nobody can be sure about all the internals.

Here is a site that found compatible parts for the Fiero.

http://www.fierosails.com/PartsManual.html

If you stick with the 2.5 VIN R that were in the fiero's they are mostly the same but had several changes for example:
Heads changed in 87
Went to roller cam in 86
Oil pump changed in 87 or 88?
...

Here is a good link to changes:
http://ironduke7.tripod.com/dukevariations.htm

quote Originally posted by DisplacementIsKing: If you stick with the 2.5 VIN R that were in the fiero's they are mostly the same but had several changes for example: Heads changed in 87 Went to roller cam in 86 Oil pump changed in 87 or 88? ...

Roller cam was 1985.
Oil pump was 88. It changed with the introduction of balance shafts in 1988.
There are a few different pushrod lengths.

Keel, I think it'd be easier to answer your question intelligently if you told us what you are trying to do.

quote Originally posted by KurtAKX: Roller cam was 1985. Oil pump was 88. It changed with the introduction of balance shafts in 1988. There are a few different pushrod lengths. Keel, I think it'd be easier to answer your question intelligently if you told us what you are trying to do.

I have a lead on new g.m. 2.5ltr crate short blocks 86 and 87's. but they are the ones for the grand am/ buick somerset/etc. that I've read the block is shorter and doesn't have the off set water pump
But if the rods, crank,pistons, etc is the same.. 299.00 for all new parts.. and dump them into my Fiero block.

If you know what car the blocks are supposed to go into, you can cross-reference part numbers on the Rock Auto website. It's not a quick process, but it is probably worth the effort.

quote Roller cam was 1985.

DOH! :P

quote There are a few different push rod lengths

The roller cam motors have a different length then the flat tappet.

quote I have a lead on new g.m. 2.5ltr crate short blocks 86 and 87's. but they are the ones for the grand am/ buick somerset/etc. that I've read the block is shorter and doesn't have the off set water pump But if the rods, crank,pistons, etc is the same.. 299.00 for all new parts.. and dump them into my Fiero block.

Nice!