Floor pan/ frame connectors

Since the floor is essentially the entire supporting structure for the middle of the car and I cut it out first how would I safely support the car while I'm doing it?

There's alot of info out there on it. Some guys weld in a temp brace in the door way from where the door bolts on to where the striker post is. While not an A body here is an article that might help you some. Good info here.

http://www.moparmusclemagazine.com/...g_challenge_or_a_resurrection_tech/index.html