I am looking at buying a 1978 model year 98 that the doors aren't great. And I have a 1983 98 that has good doors. Will the 1983 doors fit on the 1978 car?

 

Do you mean the doors are rusted or they have body damage? Do you have a sedan or a coupe?

Check out this thread:

https://classicoldsmobile.com/forums...lta-88-a-8787/

 

Am going out on a limb - but am guessing the outer skins changed in the '79 to '80 model year changeover.
meaning '77 to '79 interchange, and '80 to '85 interchange. Guts and glass may have stayed the same. I've never bought big car stuff from that era, believed it too hard to sell. Now it's too expensive to ship.

 

The doors on the car I want look like they are rusted at the bottom. The car is out of state from me so won't know until I get to look at it in person. Waiting on an insurance payout.

 

Call a local salvage yard, they can check their interchange catalogs.