74 and 75 coupe frame differences

[Savior of the 75]

Recently, while saving my sister's car from the tow shop, my father and I discovered a '75 classic white L48 coupe sitting in derelict. Upon further investigation we discovered the vette had been in storage there due to its being reposessed by the bank some 4 years prior. Well long story short we, ended up with the car after making a bid and discovered that the frame section near where the rear trailing arms connect to the frame had been rusted nearly completely through. Right now we are operating on the assumption that if there is one section rusted this badly then we can't just patch it up and expect the rest of the frame to hold together. We have been looking for a replacement for several months now and the best we have been able to find is a frame from a '74. Will the frame from a '74 fit under the body of a '75? I know from what research I have done that there are minor differences between the '74 and '75. But are there differences so big that could make this '74 frame unusable? If the differences are minor then what modifications have to be made?

 

[Culprit]

Welcome to CAC! There are lots of smart folks here who can provide some input for you.

Semper Fidelis,
Culprit

 

[Robin7TFour]

welcome Savior,,,,always wanted to say that! JohnZ will be a good source for that answer. also you may want to ask the NCRS rep who handles the 68-82 tech info.
glad you rescued the 75. i wonder how many others are lying derelict?
Robin

 

[Savior of the 75]

Is there another online reference that would have this information available? Such as maybe someone's frame off resto of a '74? I got lucky and found photos of someone's frame off restoration of their '75. Would anyone know where I could find someone's frame off restoration photos of their 74? Thanks

 

[smokedtires]

Sounds like this is a good candidate for an aftermarket "back half" frame rail & suspension setup Depending how far forward you might have to go to get solid frame to weld to, it might be an easier way than finding a good used 30 year old frame . So if your plans aren't to restore it to NCRS specs, have solme fun with this car :cheers:

 

[SG4206]

Over the last 30 years ; I've seen many C-3 frames switched from '68 - '79 bodies. I even knew about a '65 frame with a '69 body on it . Where there's a will , there's a way.

 

[Thumper]

The only differences that I could possibly think of would be the bumper mount brackets. And if they are different, which they may not be (and I really think they are the same), you can use the brackets off of your rusty frame. If you've found a solid 74 frame, I'd bet it will bolt up with no problems whatsoever.

 

[norms72]

I think the only difference that could cause you any grief is the rear bumper mount. From what I have seen, the frames were essentially the same from 68-74 (even with the addition of the rubber bumpers), 75-79 and 80-82. The main difference between 74 and 75 is the last 18" after the #4 body mount (made larger and with a different rear crossmember for the bumper shock absorbers). If you replace the last 18" with the same section from your old frame (provided it is usable) you should be off to the races. I have a really nice frame from a 79 that I plan to put under my 72 after I make that change. It is an honorable thing to bring an old soul back to life. Good luck and welcome!