never seen that exact type before but, are you sure you have that front perch the right way around - isn't the threaded nut supposed to be to the inside... as in toward the frame??
They are correct, if I swapped sides I'd move the springs more outboard. The stud spacing is correct compared to my originals. The nut is on the opposite side to ones I've seen online as well. I picked up these and the shackles for 40 bucks from a guy who was going to use them on a 68 dart but changed his mind.
