A T-bar crossmember may look perfectly fine on the outside, paint and everything, but the crossmember rusts from the inside out. Water, even from washing the car, migrates down the inner fenders onto the top of the frame rails and into the rails and crossmember. Combined with dirt, now mud, it sits there and rusts. I have pictures somewhere of a twisted out t-bar socket and the crossmember wall is paper thin.
I was driving a 69 cuda home from where it had been stored at a body shop. I got within a couple blocks of home when BAM! The front end collapsed onto the bump stops. That turned the A56 'cuda 340 into a parts car. Back then, repo parts weren't available. Any older Mofan who lives in the rust belt knows about this. The front frame rails under the firewall where it kicks up to accept the UCA's is also very susceptible to rust. A lot of A-bodies got junked back then even when only 10 years old.
