Ron,
I did some research on shocks previously and will share what I found and based upon personal opinion;
A lot of people seem to like the Aldens, to me they are damned expesnive and have a tendency to leak, as they are basically Hot Rod shocks not street/strip. I have a set of the Hall Alden's (Alden bodies with 4.5" dia Hall springs) and they will be coming off the car and getting replaced, mainly due to the fact they are 480# FR and 600# Rr spring rates that are just too damn stiff for me.
The HAL/QA1 (previously Carrera) shocks appear to be about the best cost/function compromise available. At least one of the vendors (Larry Stock) is selling these as direct Pantera replacements.
The QA1's are available in single adjustable or double adjustable and when I contacted QA1 Tech they recommended the 'DR5855' model, either DR5855P (Single Adjustable) or DDR5855P (Double Adjustable). Note: There is also a 'B' suffix version to each of those part #'s for bearing application instead of 'P' (Poly bushings), so make sure you get the correct one.
The DR/DDR5855's are 17" uncompressed length and 11 5/8" compressed. They have a recommended ride height of 13 1/4" to 14 1/2" which would seem to be where you are at. They use a 12" long spring available in multiple rates. The beauty being Summit Racing sell the shocks (bare shock bodies $170 single adjustable, $285 double) and springs at $37 ea. making obtaining springs for rate changes pretty easy. Larry Stock's package is around $1100 for the single adjustables, but he says it comes direct bolt on with fabricated bushing inserts, whereas you may have some fab work if you go the Summit route.
See QA1's website and catalog's at
http://www.carrerashocks.comSpring rate recommendations seem to be as individual as Pantera's themselves dependent on your use. Larry regularly races (ORR and track) his narrow body Pantera and has 375# Fr with 400# Rr spring rates. Personally, I will start out at 350# Fr and 450# Rr and go with a 1" solid sway bar with the ball ends on what will be a wide body car that is intended to see some track use.
Hope this helps some,
Julian