I am installing new full lenght floorpans in my 67 chevelle, I noticed there is a raised portion in the new pans where it meets the frame mount. Are you supposed to weld a nut to the bottom of this? do the bushing bolts come up from the bottom? Any help here is apprecited with this task

I replaced the pans on my 65...if your 67 is like the 65...there should be a cross brace for the floor pan and the nut is in the brace that the body mount bolts to...hope that helps