Frame Connectors?

I used the mopar performance bolt on deals.Kinda cheapo, but they work.

Had to use washers to shim the fronts a bit and drill some holes to bolt the rear sections in.

Then I welded them wherever they touched the floor and welded the front and rear areas fully at the perimeters.

They make better, perfect contour fit ones for E and B bodies I believe, but I'm not sure about A bodies yet, and some guys fab up their own, cut the floor pans and go crazy with them.

I'm sure someone will chime in with some more answers for you.