You may need to call them and give them the size and eyelet configuration of your shocks. I believe that the rancho catalog has all the dimensions in the back. A good counter guy should be able to look all this up for you...
I think the Rancho # is 99116. I found it in the June 2005 Car Craft that featured a Comet project. I plan to replace my Lakewood 50/50 rears with a set of Rancho shocks next year.
I bought cheap no name shocks for the rear of my '75 4dr.It pulled 1.70 60' times on g-60 M&Hs w/no slappers,stock springs.I didn't want the drag type shocks 'cuz I drove it everywhere and it already didn't handle that well.
Best I have found for drag racin too. 6cyl. springs with slap bars snugged against the spring, M/T's 28x 9in slicks, 90/10 fronts. 1.42 60's with 331 motor.