Chevy Interchangeable Parts Manual
Parts interchange can get complicated. They are only listed as interchangeable when they are straight up bolt-in swaps, which for a shop is good, but for a home mechanic or for a project isn't critical.
Chevy Parts Interchange Manual
On many GM vehicles, the engine from a 2 wheel drive and 4x4 are listed as not being interchangeable. When the only difference is just a right angle adapter for the oil filter that's held on with a single bolt. The most common change is the nose piece that holds grill and headlights, if fenders and hood are listed as usable, but grill isn't, then the nose can be swapped as a complete unit. Second most common will be the entire front clip, if doors and windshield are listed as interchangeable, then the entire front clip can be swapped. (example 80-86 f150 fenders won't interchange with 87 to 91 f150s, but the whole front clip will.) Sometimes the only thing that keeps a body part off the interchange list is the trim package, a base car model is listed as not interchangeable with a car that has ground effects even though they are identical parts (except mounting holes) under the bolt on package. Best way for project cars is to check for a website on the car you are working on, almost certain to find one, I mean heck there's a site for Yugo fans. Another is to check wikipedia, most models have a web page and enough detail to tell you if the changes were redesigns where the whole thing was changed or cosmetic upgrades where only bolt on parts were.
Then of course you have the 'partner' vehicles,like the Ford ranger/Mazda B series, Pontiac Vibe/Toyota Matrix, as well as the badge cars, Olds, Chevy, Pontiac etc, different parts, They are not listed as being able to interchange, but all the same when it comes to bolting them on as a complete unit. Of course if you are restoring something, or if all you need is one part, then look for the correct part. But if you just need to get on the road and can't find the parts, or simply like the newer look, knowing what to look for helps. This reminds me of a quandary I ran into years ago. I had a 1965 Ford Galaxie (former police cruiser) which suffered front end damage in a parking lot. I could not find a front clip for it, but did locate one for a 1966 model.
The difference was the contours of the fenders which were VERY square on the '65, but were decidedly ROUNDED on the '66. The two were mounted identically with the same hardware, so I installed the '66 parts & re-painted to match. It became quite a comment magnet as the rear tail lights were SQUARE on the '65 model and ROUNDED on the '66. I enjoyed it that way for another 8 years until someone unfortunately rear-ended me at a stoplight in 1981.
That car was a muscular beast with the interceptor tuned engine which was standard with police cruisers at the time! Top end was around 140MPH which I verified on an old country road one clear cold night. A friend of mine had a 1976 Ford Granada which came from the factory with all IDs on the vehicle saying Mercury Monarch. They of course came down the same assembly line, but still, Quality Control? Interesting you bring this up! A friend in high school purchased a 1971 Chevy Nova new.
The outer body said Chevrolet Nova, but all the interior aspects and badges, as well as the engine were marked Pontiac Ventura! He did not notice it for several days, and when he took it back to the dealer they tried to EXCHANGE it for another car, with maximum dealer options.
His car was stripped down base model. He declined the offer, as he felt he had a truly unique vehicle and wanted to keep it. GM contacted him directly weeks later and offered him a full replacement (.FREE.) and a full refund on his purchase, and he still turned it down!
Unfortunately his older (alcoholic) brother took his car out without permission and went on a drinking binge and totaled it against a tree 2 years later. He never forgave him for it and they haven't spoken for over 40 years to date! I have heard of things like this happening during a production line change for 'sister models' which the Pontiac Ventura (as well as the Buick Skylark I believe) was, but this is the only one I ever actually saw and rode in for almost 2 years. I think I would have taken the offer from GM, and would have likely tried for a model upgrade at that!!