i dont know... it kinda seems like the front part of the spring pack on my rear seat back is sagging due to 55 years of gravity and 3 layers of upholstery. i stripped the frames and fit 'em up. the bottom doesnt seem to wanna slide all the way under the back. the front part of the seat frame (spring pack) seems to be an inch or so 'lower' than the actual frame...is this normal? am i stoned? can i 'lift' the front of the seat back to make things all groovy? i've been staring at this thing too long....