Before I begin...

[Dreamcar]

Soon I will be purchasing subframe connectors for my 69. I am getting the ones that are cut out to follow the shape of the floorboard. However, I also need completely new floorpans. 

So, my first question is...can I tack-weld the subframe connectors in place without welding them to the factory floorpan before removing factory floorpan? My thinking is that since the subframe connectors have cut-outs for the floor, this would help guide the new floorpan in place.

Second, the engine+trans, k frame and axle our out. The rockers are solid. How much temporary bracing does the car need if sitting jack stands (eight in total) once the front floorpan is out and the doors are removed? Should I add bracing?

[tsmithae]

My  is to add bracing in the interior if you are worried about the body flexing at all and replace the floor first.  The new floorpans won't be exactly like the old and the contoured subframe connectors do need some massaging and grinding to make fit perfectly. I would hate to see you get them to fit perfectly with the old floor and then have the new one not sit properly atop the connectors.  I just did this on my car and I wouldn't do it any other way, personally. 

I wound up having to use a jack to hold the connectors in place against the floor, marking the high spots, grinding them down, test the fitment again and then rinse and repeat until I was happy with them. If they are welded in place first you will be having to pull the floor up every single time in order to grind on the contours of the SF connectors, which was way more of a PITA with a full floor.

[Dreamcar]

Thanks for the advice!