I am in the process of taking the body off a 66 SS
So far I have broken 5 of the 6 bolts that I have attempted to remove. Any advise on how to repair?
Can I just weld in a new nut on the crossmembers?
Thanks

With welding skills anything is possible!

I broke two when I did my 69 elky. I drilled mine out but it was a PAIN! Darn things flop around. Start with a 1/8th bit and work up to a 1/4th bit the rest should chisel out. This will take TIME.

If you weld a nut to the crossmember you will not have the adjustment to center the mount in the frame holes.

Good luck, Ron