Unfortunately I bought the large pans. I've read all kinds of stuff on the subject. My car isn't too bad. rear driverside along the brace,the brace it's self is solid. under the pedals is the worst. and rear passenger a litle bit along the brace. Anyway my question is. Do you cut the whole pan out and weld to the frame? Can you just cut the rust out and por 15 both pans and weld it on top of the existing pan. I'm not looking for show car quality, I just want it to be surcure and rust proofed.

The floorpans are not welded to the frame-floorpan to floorbracing is welded but NO part of the body is weled to the frame on a full frame vehicle.
Here's what I did. If your sure the new pan is bigger than all the rust area to be removed then go ahead and cut out all the rust. Drill out the spotweld that hold the floorpan to the floorbracing. remove rusty panel. Lay the new pan inplace make sure you have plenty of overlap of the new panel to original floor.
Next is for you to decide are you going to buttweld the panels together or overlap and weld? You decide.
Then mark and cut new floor accordingly.
Now drill-thru the floorpan only about evry 8 inches at the floorbrace contact points,you'll put rosette welds here to weld the new floorpan to the floorpan bracing. Once youve got that done then you can start welding along the outer seams.
Por 15 after all welding is complete. If you use overlap method fill the seam areas with seam sealer

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Philip Mullaly
72 TPI El Camino
You can never fix a Ford,You can only work on them alot.
The Z-meano (http://www.chevelles.com/showroom/Caminoside.jpg)
Cowl induction injection (http://www.chevelles.com/showroom/tpienglft.jpg)

tHANKYOU Philip