As far as economical, rebuilding the original suspension is the way to go. On the other hand, if you want ifs, there’s plenty of options out there when it comes to MII.
Speedway, CPP, and others all have economy kits. I recently purchased an “economy” crossmember from CPP and control arms from Jegs. The crossmember is top notch, I may clean up some welds on one spring hat, but it’s more of a cosmetic thing than anything. For a little over $200, I can’t complain. The control arms were a good deal too, I may swap the ball joints out, but I don’t have anything bad to say about the quality.
I haven’t seen anything out there for 36 trucks, but there seems to be a number of 37-40kits available.. If nothing else, you could buy a universal crossmember and build it out from there.
