I ran the kit on my 81 and it was horrible. The shocks were really bad and the leafs were very stiff. Flex was non existent! The only thing the kit is good for is giving your truck a lift and that's about it. Probably recommend going for the Marlin 4" kit, I have that on my truck and it flexes really well and rides well on the street. Get crossover steering too while you're at it...
Regards,
Nathan