I've used Caltracs before if you don't clamp the springs tight they will make the rear jump up & unload the tires
The Comp engineering set with the rubber joint didn't seem to hit so hard & created less shock

Stumpy I don't know if you want to level it or not But you might want to try cutting the rear segment on the bottom two leaves this with clamping them helps kill wheelhop
I did that on a ShortBed 440 truck that I had that ran 7.40'S 1/8 mile with totally stock suspension budget modified & using drag shocks & /6 springs 29X10.5 Required
I put 200# ballast bar on the very end of the frame with the battery & fuel cell back there too.