The repop will be a pain to get it to meet up to the bolting positions to the repop quarter. It will never fit in there and be a nice joint, always looks buckled out there. Consider cutting off the flange where it meets to the quarter, and welding it on solid to the quarter. Worked out good for me, and spent alot less time F-ing with it. You can still get at the gas tank, bumper bolts, shackles doing it this way. Those parts are a little harder to get at, but still do-able. If you do it this way, make sure the shackles will come out, otherwise, there isnt much room to hammer on them with the vallence on.
That's exactly what happens, you can either have the top of the valance square with the bumper and a nice fit but the sides will be bulged out, or you can have the side joints nice but a big space between the bumper and valance, Challenger6pak said there might be a quarterpanel aignment problem, thats true, I have all the pieces screwed together and was hoping to use the new valance to tie everything together so I could weld the outerwheelhouses,trunk extensions, trunk floor and quartersskins, but I really don't have anything to reference off of now, since I cut the original quarters off ! (lesson #1 don't cut anything off till your sure you won't need it) Anyway, this topic pretty much answered the basic mounting bracket question, and also shed new light on the reason for the valance looking like crap.