[davepl]

Well, even if its not the cause I wouldn't be driving it over 55 until that was fixed anyway! But there's a good chance it's the cause, I'd say.

Remember GM built 875,000 of these in 1972 alone and it was a 6 year run. That means there are a lot of old factory cross members out there, but the repops might be decent too. Unless it's bagged/chopped/lowered or whatever you kids are doing these days and requires a special crossmember for ground clearance or exhaust routing.

Just a random thought, and I'd check with a frame guy first, but: if you could get a bottle jack in there and place to seat it, I wonder if forcing the crossmember out straight again might push the outer rails back into position.

I guess you'll know when you try to install a new one whether it fits or not!