Box the frame
 

Has anyone boxed the frame at the open area under the doors
on a 70.
any pics.
atb mick.

I have not done it, I am just beginning the tear down, but there are kits that sell the plates pre-cut and bent.

Power Block Muscle Car just did one on a Monte last week. I did reweld all my joints on my frame and smooth all the welds before I re-assembled my car.