Lots of clamps make the fit easier to make. I used my favorite GM tool to get the pans to the correct curve to meet the old floor contour. Several fittings and trimmings prior to welding. It took some hammering to fit the front. Be careful not to bend the floor-frame extension lip (under the pan) while adjusting the pan. I had to come back after I had begun welding to hammer it back from the bottom (that sucked).

Another shot of the rear of the floor pan. The pink tint in the Inner rocker is caused by using a red brush in the white primer. It will get a coat of gray before it is all over plus blue then carpet anyway.