I have a 91 single rear wheel W350 and it came from the dealer with short blocks over the axle where the spring sits. The truck looks feeble with the bed sagging much lower than the front end. I noticed that a 92 and 93 trucks have a 4 or more inch block as a spacer to raise the rear. Does anyone have a pair of these or know where I can get some for my truck. All the kids in town say it looks "Weak". Thanks.