1980 donor car to earlier model compatibility
 

I recently moved to california from the north east and bought a house here. In 2002 my father and i purchased a 1980 corvette and fixed it up together over a few years. At that time the frame and birdcage was ok...

So when I got a house out here he shipped me the car. The car was in the north east from 2002-2013 in a garage however in 2013 he was stored outside covered in florida. My mistake was not checking everything before getting excited about the car when I got it here. Now that I have a decent job i wanted to fix this car up to how I wanted it.

Like an idiot I should have checked everything out first before putting about 35k into the car so far including entirely new drivetrain, everything in the engine compartment, new front and rear suspension, rebuilt everything in the doors, new windshield, custom gauge cluster, all new powersteering, sidepipes, seats, and im sure a bunch of other little stuff.

So this past weekend I gutted the interior and was going to install some speakers into the kickpanels and oh boy...you know what was coming next. its bad. the A pillar bases are rusted terribly some of it isnt attached anymore. So then I checked the B pillar bases... not good. I am going to do my best to provide some structural support to it over the next few weeks and then just drive the car for a few years hoping for the best.

So now i get to my question..

When the time comes and this car is no longer able to be driven safely ( not even sure it is now..) I am thinking about trying to find an earlier C3 model pre 75 ( califoria smog laws..) that has a solid chassis and birdcage and move over as much as I can from my 1980 to that car. How much will be interchangeable? Anything that you can think of is so vastly different that it wont work?

Quite dissapointed I didnt see this sooner but it is what it is. Ill keep my eyes out for a earlier c3 over the next few years at the Pomona swap meet and see what i find.

Welcome to California! Sorry to hear you found rust issues. Here's what I think will probably be compatible:

- entire drivetrain (except the diff/rear suspension)
- seats will probably be OK (with some minor mods)
- front suspension
- side pipes (wouldn't have passed smog with those on the 80 though)

Not compatible (without considerable work):
- dash and gauges
- door panels
- rear suspension (some parts might, but 80+ has the 'batwing' rear suspension)

You didn't provide specifics on your engine/tranny, but keep in mind that manual tranny cars have a welded-in tranny crossmember, but automatics have a bolted-in crossmember. The bolted in crossmember will work for either manual or auto.

FYI - you mentioned 'pre-75', but 75 is also smog exempt. Just stay away from 76+ if you're worried about smog check. :cheers:

Yay california lol.

thank you for the reply!

the engine is a 350 HO crate from GM . Trans is 700R4 from bowtie.

The sidepipes may have gone on after smog..lol. Dougs stainless steel headers and pipes with reverse flow inserts.

The rear suspension is this

https://www.ecklerscorvette.com/corv...1980-1982.html

I do not know much about the suspension on models other then 1980 but im guessing this wont be too easy to use on an older model?

Would it be possible to literally just remove the entire doors from the 1980 and put them on an earlier model? I rebuilt nearly the entire doors, locks, latches, power windows, power locks with all new parts and brand new leather door panels and i would love to be able to when the time comes just remove door from hinges and throw on another car.

with respect to the gauges for the speed and tach I used the original housing along the outside but made new mounts for the gauges, combo gauges from autometer so i eliminated the center cluster and moved everything to those two gauges. I was hoping the housing is about the same size and maybe I could just take the entire housing unit ( see attached pic) and throw it on my next car without too much work.

https://cimg9.ibsrv.net/gimg/www.cor...c7036f239c.jpg

https://cimg3.ibsrv.net/gimg/www.cor...701091205e.jpg
https://cimg4.ibsrv.net/gimg/www.cor...3892e89fbe.jpg

This is what made my heart drop. Going to clean this up this weekend and reinforce the best I can after removing the rust, applying POR15, then bracing that area a bit with some metal and then some structural epoxy to buy me some time.

Should transfer without too much fuss.

LOL - I may or may not have to change the exhaust for a day on my 79 every couple of years. :D

The earlier models can use the mono-spring, but I think it's a narrower spring?

This might work, but not positive. Maybe someone else can chime in?

The speedo/tach (and dash) on 77 (?) and older are totally different. Look up a picture of a 75 dash via a google search, and you should see what I mean. You can probably re-use your gauges, but it'll need some fresh fabricating (which looks like your ok with anyway!)

Thank you for the info bradley. Much appreciated.

Both vansteel and vbandp list the composite springs as being the same all c3s. So the only thing that will have to change is the strut rods

As far as safe to drive it like that the bird cage is part of the body that sits on the frame. If your frame is good the worst damage I think it could do structurally is door sag, windshield cracks, top not fitting correctly and fiberglass cracks. Not to mention reduced crash protection. If you want to clean it up and POR-15 that will stop the rust on the inside but not on the outside. It could buy a few years.
The main thing I'd look at are all the body mounts and also the trailing arm pockets for similar rust. Check the front crossbar and radiator support and radiator support cross members too. These are the areas where it could compromise safety.

The frame has some rust with the worst being at the front right radiator support. I saw that before i replaced the engine but I didnt see much else that was concerning.

So far no door sag, they close perfectly. The frame around the windshield is pretty good ( didnt remove dash to see lower). I had the windshield replaced last week due to scratches from windshield wipers.

So far my plan is do really clean up those A pillar bases tomorrow, coat them in POR 15 and then make a brace from the pillar to my steel floor pans to provide a little bit of support and then put some POR15 epoxy around the area. I considered supporting it to chassis but then figured it might make it worse by doing that.

I installed a speeddirect spreader bar to help with a little bit of chassis stabilization and may pick up a sharkbar to offer some more support for the birdcage.

Other then that I am just trying to buy as much time as I can before it becomes more of an issue while keeping my eyes out for a early c3 convertible without an engine or trans.

I definitely have some concerns if i were to get in an accident but dont want to pour too much more money in this car and make a roll bar or anything. This car will never see a track. It will see the parking lot by my office and weekends at the dog beach lol.