1974 Rear leaf spring perch
 

The front perch mount bolts just spin. What can I do to get them out? And what options do I have to fix them. How do I get to the nut I do not see.

I just went through this on my 79. I torched the head off the bolt, removed the spring mount and got new "J" nuts for reassembly. It's a bear to get the old nuts out, I had to cut them as short as I could, but, it can be done. Use anti-seize when you reassemble and leave the spring bolts loose and torque them with the cars weight on them. I did mine with two 3/4" hand wrenches.