I have installed my Package Tray for my 1969 XR7 from WCCC part number 42105. The package tray is an inch short side to side when centered. Am I doing something wrong here? The package tray is 54 1/2" across the middle. It appears that it should be 55 1/2". Do I have a wide body XR7? 
WCCC does not have an alternative so it appears I will need to build my own. Has anyone sourced the mesh material to go over the fiberboard?
Maybe you are missing the fiberglas insulation behind the sail panels? It ought to be about 3" thick on each side.
Royce, I’ve never seen that on a 69 or 70. But have on 67 and 68.
I have an original package tray liner, I’ll go make a measurement of it.
I have the insulation behind the sail panel supplied by WCCC. It is only around 3/4". 3 inches would definitely fill the gap.
It compresses down to maybe 1" per side. Hopefully Neil will give a measurement but I think you are OK there.
I finally got done measuring the original, and a reproduction one I’ve had for about 8 years. Both are 55 1/8 at the front edge, closest to the seat back.
I measured mine the same way you did and got 55". So, I have to pull the bottom of the sail panel out a half inch on both sides and use some more insulation to fill in the gap. The insulation behind the sail panel appears to be less than 1/2" thick. I glued the skirt along the bottom to close to the pillar.
I figured the sail panel fit flat against the pillar all the way to the package tray. The package tray the car came with was warped by rain and a leaking corner so it did not leave any useful marks.
Thanks for the help on this Neil and Royce.
Correction. Warped by sun and a leaking corner.
The WCCC item should have a score along the back edge for bending it upward under the back window. That shoud make it fir.
Mike M.
I finally discovered the perforated edge and that slid it back correctly. I have my sail panels pushed up against the pillar and so it looks like they need to pull out on the bottom to fill the gap between the package tray and the pillar. I have not checked to see how the rear seat fits into the gap issue yet.
