I have removed the floor pan from the front seam to the base under the rear seat. In doing so I found the floor pan braces should also be replaced. So now I need to lift the body to remove the braces. Question: Should I install braces in the body before lifting it since a large portion of the floor pan is removed? if so would one brace from rocker to rocker and one from the remaing tunnel to the rear set be adequate? Car is a 69 2 door hardtop.

You don't HAVE to lift the body to replace the braces......

I am helping a friend replace the floor braces and floor pan on his 65. He did not want to lift the body, so we had to be creative. His car was a racer, and will never be "restored" so we didn't have a problem cutting on it.

What you may find is that the inner side of the rocker where the brace welds to is either thin as tin-foil or is already rusted out.

He had cut enough of the floor pan away so we could get a good look.

We cut the floor sill on either side of where the brace is and peeled it back (after seperating the spotwelds on the floor from the edges of the sill). This gave us room to bend the inner rocker edge, and remove the rusted remains of the brace. We used a long blade on a saws-all to cut the inner rocker. The bottom of the inner rocker is spot welded to the front of the inner rocker, so drill those out and don't cut into the front rocker.

I hand-fabbed some flanged patches, which will be tacked to the brace in place, then we will pull the brace/patch and weld it up. Once they go back in the welder can reach the inside of the rocker to weld the patches in from the backside of the inner rocker.

But if you are going to raise the body AFTER you cut the floor you probably need to weld in some 1" square tubing to provide support. Maybe an "x" across the floor. and maybe one diagonally from the door sill to the jamb?

Thanks DG, after looking at this for some time and also deciding to go ahead and install new body bushings I think I will brace the body and lift it. If it doesn't work I may have a bunch of parts for sale in a few days!

Here's an alternative to separating the body entirely from the frame. This comapny sells a set of stand-offs that may give you enough working room to replace those braces.
Stand-offs (http://www.accessiblesystems.com/bul/bulso01.htm)