Need help removing nut that holds shock in place, I've tried heat, a hammer and chisel... Options

[914 RZ-1]

I'm trying to remove the nut that hold the shock in place. I need to replace the strut.



I've tried heat, but maybe it wasn't hot enough. How hot do I get it?

I'm using an 18" pipe wrench. It's the same one I put it on with. I changed the shocks about a year ago. It will not budge. It's hard to put leverage on when it's in the vise. I even hit the wrench with a dead blow hammer. It's currently soaking in penetrating oil.

I tried using a drift and hammer to break it loose. Didn't budge.

The next step would be to use a cheater bar on the wrench. However, I'm afraid I won't be able to hold it in the vice securely enough.

Does anyone have any other ideas?

Thanks!