75 Frame for a 73 rebuild?

[73vettecollector]

Vette Lovers:

Awesome forum here. Quick question... I am rebuilding a '73 L82 4 spd and am thinking about replacing the frame. A friend of mine has a 75 automatic car minus engine/trans, and is willing to sell me the frame.

Is the 75 auto frame COMPLETELY compatible for my 73 4-speed?

Thanks a ton!

David

 

[I_R_DA_ONE]

The frame on the 1963 through 1982 was pretty much the same thing... the only differance was a few mounting pads.... and these can be welded on if ness.
the frames on a 1973 and 1975 should not require any modifications.... check them both for rust and have it sand blasted and hot dipped to clear up any rust issues

 

[Mac]

Only operating on memory here but I think the auto tranny frames had a bolt-in tranny crossmember whereas the manual tranny frames were welded in.

-Mac

 

[Vettehead Mikey]

The rear bumper area would need a lot of fabrication work done. '74 and up had a very different configuration in this area, compared to '68-'73.

 

[73vettecollector]

What does "a lot of fabrication" mean?

The rear bumper area would need a lot of fabrication work done. '74 and up had a very different configuration in this area, compared to '68-'73.

Thanks for the reply, but what does this mean? One poster said the frames may only be different for the tranny x-member, another says the rear is different.
Please expound!

David

 

[Vettehead Mikey]

Mac is correct that auto and manual frames had a different crossmember, but this is a serviceability feature only, so these frames are interchangeable.

The big difference for '74 and up is the support structure for the 'new style' rear bumper. It's nowhere near plug and play. A good welder could remove the features from the old and adapt them to the new. Usually the tail end of the frame is reusable, barring previous accidents.

 

[norms72]

Quote:
Originally Posted by Vettehead Mikey
The rear bumper area would need a lot of fabrication work done. '74 and up had a very different configuration in this area, compared to '68-'73.

I'm in pretty much the same boat. I have a frame from a '79 that I'm doing up for my '72 when the time comes.

The main problem as stated is the rear bumper area. The frames are pretty much the same up to and including the #4 body mount. The transmission crossmember shouldn't be an issue. You will have to weld on the clutch bracket that the automatic frame won't have. In '75 they changed to the telescopic bumper mount and the frame channel just past #4 body mount was enlarged and reshaped to mount the bumper shock. By grafting in the last 18" piece (just after the body mount) from a '68 to '74 you should be OK. I believe this has been done by members of this forum in the past so with any luck, they'll pipe in with their $0.02 worth. Good luck!

Norm.