I'm in the process of replacing the rear leaf springs on my 75 e150. I've got the left side done and out of the way. On to the right side. I got every bolt removed except for the forward leaf spring bolt. The nut is off of it, but the metal bushing is stuck to the bolt preventing it from being removed. I can turn the bolt with a breaker bar while pushing on the back side with a big pry bar and it will not come out.
I'm not sure what to do now. I have a torch. Should I cut through the leaf spring and through the bushing? That's a lot of material to burn through.

 

Your dealing with "Rust-Weld". The bolt rust-welded itself to the sleeve and the sleeve has spun out of the rubber bushing.

The best way to deal with this is to cut off the bolt, with a sawzall blade, between the spring perch and the spring, cutting the rubber bushing/bolt, that way you do not damage the spring perch.

The bolt is easy to replace with new, the spring perch is not that easy to replace. Yes, I understand that your replacing the leaf spring with new/newer.

You could torch thru the leaf, then you need to burn thru the rubber bushing, and that's not a clean job, rubber don't burn clean, and I don't advise that.
Trying to torch just the bolt, the rubber will burn, and you take a chance on damage to the spring perch.

Living in the rust belt, I've taken a sawzall blade to several leaf spring bolts in the pass, got the spring off, and replaced the rubber bushing, with a new grade 8 bolt, when re-using the leaf springs.