-77 Caprice 2 door frame

Hello all.
I am new to this forum and I live in Norway.

The other day I went to see a -77 Caprice, 2 door coupe for my son.
It is a project car since the engine is half way dismantled with one of the cylinder heads removed and the left rocker panel had a big hole in it.
However the more worrying thing was that, despite the owners statement, it was a big approximately 4 inch rust hole in the bottom of the frame behind the rear axle.

I was not surprised (well maybe a little since the owner claimed the frame to be rust free) because these cars tend to rust behind the rear axle.
Now I am suspecting that the whole rear frame is just toast. It was very difficult to inspect the rest of the frame.

Since the guy had a 4 door standing just opposite this car I started thinking whether the 4 door have the same frame or maybe that at least the rear part of the frame is the same.

Anyone know if the 4 door and the 2 door share the same frame?

Per

2 door and 4 door share the same frame. only the station wagons are different.

Thanks.

I know it is an old thread but the frames are the same from 77-95 for the caprice and impala, the only difference I found is the passenger side motor mount is slightly offset. Also the newer frames are more prone to tearing under impact than bending.

The frame for the 94, 95, and 96 have 3 differences from the 1977-90 frame:

1. The rh engine mount offset rearward to give room for AC compressor (you need an LT1 or LT 4 block to use this frame)
2, The transmission crossmember mount is different allowing you to have true factory exhaust when using the welded stamped crossmember
3. the diagonal braces for the front crossmember are welded in, not bolt in.