Removing rear springs in a '70 mach1

tried heat..no luck

I tried heat, didn't work. The C Clamp sounds like a good idea. I've given up for the day but will run out and purchase one tomorrow. Thanks for the tip xoxobxfx. The impact hammer sounds like a good idea, but I don't own an air compressor...yet. If I don't succeed, I'll be back. Thanks All!
 
Do this if there is space: get a large socket that will fit over the bolt head with room to spare then use the c-clamp on the opposite end of the bolt and on the socket. the c-clamp will push the bolt into the socket. I've used that trick on many a bolt and u-joint and it will work if you have the clearance.

If that wont work, get another bolt, slightly smaller than the leaf spring bolt. Get a a long nut and thread it onto the bolt. Stick the bolt between the sheetmetal and the leaf spring bolt and start unthreading the nut. If all goes well it will push the bolt out. This will work well so long and you can keep the bolt that you're unthreading stable.
 
All good ideas. If it still doesn't come out, just use a Sawzall with a carbide blade and cut through the bolt on each side of the spring. A new bolt will only cost you a couple bucks.
 
It will most likely be next year before it's at that point. Next the body will get mounted on casters and the shell gets an aircraft stripper bath. Then it goes to the body shop for the winter. I can't wait til it's done! :D