No, not likely. You do not "just swap in" an 80-82 rear end. It mounts completely differently. The 80-82 rear incorporates the rear end crossmember, into the rear end casting itself. The 79 and earlier rear, has a rubber mounted crossmember, that's attached to the frame, and then the rear end center section, bolts to the crossmember.

The designs are completely different, requiring a fair amount of fabrication, to do the swap.

The 80-82 rear is lighter, because it is cast from aluminum. It's not necessarily stronger. Because the crossmember is part of the rear end casting, they're not as prone to cracking the rear end cover, as earlier rears. I don't know if the Dana internals are any stronger then the earlier Eaton's though.

Actually, it still doesn't guaranty that it's not an 80-82 frame. The OP's car is an automatic, so it would have had the bolt in crossmember.

As you said, it may be a pre-80 frame with an 80-82 rear added, or it could still be an 80-82 frame, with the 79 crossmember bolted in, to utilize the 79 exhaust system.

I was hoping the OP would have said that it had the later crossmember, as it would have made it easier to identify what may have been done.

Some more detective work needs to be done, to find out whats going on with the OP's car. Boy, people sure do strange things, to old Corvettes!

 

gbvette62,

The plot thickens.

 

How about a picture showing where the differential mounts to the frame? A bracket would have needed to be welded on the frame for the later differential.

 

That and/or the transmission cross-member.

 

Bump

I'm still curious about this one. More pics would be very helpful.

 

Pics will have to wait. Vette is in a shop getting major redo of brake and carburetor systems.

Interesting and probably related to the leaf spring debacle is that both knuckle joints on the rear wheel drive shafts rub on the fiberglass bottom...actually have to cut small clearance holes in the fiberglass....can't find a way to adjust this out.
Maybe someone on this site has run into this problem and has a less cobbled up solution.

 

I suspected this may be an issue. I'm in the process of installing the 80-82 Dana 44 in my '73. Here is what I discovered on the difference in dimensions between the Eaton iron diff and the Dana 44 aluminum diff.





I measured from the cover flange to the stub axles.



There is about 1/8" difference between the two. The D44 measures 2"; the Eaton measures 1 7/8".

I also measured the distance to the front pinion mount hole.



I held a level at the top of the hole on the Eaton and the drew a line at that level on the D44. The D44 is 1/2" lower.

So the distance from the pinion mount hole to the centerline of the stub axles is 5/8" less on the D44.

I bought the section of frame off an 82 where the pinion bracket is welded. The pinion bracket is identical with my 73.



So the stub axles are 5/8" forward on the 80-82s. If I mount the diff that way the stub axles will hit the battery and storage compartments. Had me stumped until I discovered this. Here is a pre 1980 C3.



And here is an 1980-82



The 80-82s have a recess in that area to clear for the stub axles. Not sure why they did it but now you know.

 

Wow....thanks Kid Vette
This is exactly what is happening on my vette. This forum never ceases to amaze me....to think someone has experienced the exact same obscure problem and has the pics to clearly identify it.

So, what do you think of my fix......cut clearance holes in my battery/storage boxes and then form a fiberglass clearance cup sort of similar to the pic of the newer 80-82 version?

 

i think you are on the right track. I plan to get that body section from an 80-82 and graft it in. Somebody else suggested cutting out the corners, turning them upside down and then grafting them back in. Whatever works.