i have new front floor pans going into my 72 dart and the question is where do the spot welds go? this is an area where the floor meets the k-member to torsion mount, are the spot welds from the inside of the car, or are they underneath? ???
set your pan in place then go under the car and trace the frame edges. take the floor out again mark with a felt marker where to drill all the holes. then drill them put the floor back in and tac everything in place then you can start finish welding.oh ya before you tac the floor in coat the areas that youl will not be able to get at again with your favorite rust preventative.
I might also add my two cents on this project too. Be absolutely sure your new floor pan is fitted totally flush to the sub frame structures and not lifted in any areas before you tack or spot weld. The old floor may have some differences and you'll need to make sure the new pan lays in and is in contact with all weld points. Also when you weld around the edges do stetch welds and go from side to side so as not to put too much heat into any one area or you'll have big time warp. Do stetches of about 1 inch and then move to the opposit side and do a 1 inch stetch. Then the sides to the right and just keep rotating around doing stiches. if you try and weld continuously on the sheet metal be prepared for things to pucker, and warp. Slow and steady wins this race.
I would spray some weld thru primer on the panel that you are welding to. We use the 3M stuff at the body shop where i work. The heat from the weld turns the primer into liquid again and it covers the spots between the panels that you cant get at from the outside.
I welded the spots from the inside of the car on mine. I just traced the frame rails from the botton of the car onto my new pans and then drilled holes in the new pans to sorta kinda mach where the stock spot welds were and made sure the pan fit tight and then welded them in. Jumping around to different places so as not to build up too much heat in one area and warp the new pans.
There's a guy on this sight that does beautiful welds and even replaced his trunk pan without a spare tire well. He welded up his rea seat area too and the welds made me jealous. I can't weld anywhere near that good on think metal so I had to then touch up my welds with the grinder to make them presentable. The main thing is they're strong welds just not all that pretty.