I was re-assembling the rear section of my 82 LTD vari-ride and I believe it would be fairly easy to increase travel by 1- 1.5" by simply lengthening the stop strap, and using the new kimpex gas shock that is recommended to this sled. See attached pics. Has anyone tried this? I plan to. 1"-1.5" is a good gain when your starting with only 4-5" stock.
There are two limited factors that prevent you from increasing more. 1. the spring length that slides on the rear block and you can't get too close to strait on the pivoting elbow. But, I did measurements and test, I am pretty confident I get get over 1" easily.
I also have an 80 LTD vari-ride and this mod is not possible with this model because the rear section is different and the pivoting elbow cannot straiten any more than stock.