how bad is this rust?

cudascott said
the only measurements needed will be from inner side of rocker to outside of the frame rail where it meets the tranny cross brace and between rails at same location and between rails at the front. get the car level and drop a plumb bob floor from the rail at few places and mark on the floor also if you would feel better about it.:tard:

There's a reason why the factory manual includes diagonal dimensions for the frame. Never weld a frame back together without checking the diagonals. Straight across, rail-to-rail measurements don't always tell the whole story, you want to include some long, diagonal measurements to make sure you actually got it right.

With old uni-body's there's no guarantee that the other rail is actually straight or where it was supposed to be to begin with. Factory tolerances were only checked within a 1/4", and if the other rail was a 1/4" out you don't want to compound that error by measuring your new rail entirely off of the old one.

Frame work isn't hard, but it does need to be precise. That means a lot of measurements, and a lot of time, to get it right. The car might still drive down the road if you get it wrong, but the alignment and handling of the car can definitely suffer, and that will end up giving you headaches later when everything doesn't fit or roll the way its supposed to.