The vague nature of my truck is pissing me off...

[Davetopay]

I would like to toss a 4 inch lift on my 1970 GMC 1500, SO I start poking around under it and notice some things which seem odd....

1. Keep in mind the truck has no suspension lift kit now. It is sitting on 31's and they fit like they are stock.

2. It has 4 inch blocks between the axle and leaf springs(6 leaf packs) in the rear. I don't THINK the factory built them like this, but anything is possible.

3. The front springs are a real puzzler. They look like your standard 2 leaf half ton negative arch springs, until you look twice at the driver's side. It has a THIRD leaf which is only about a foot long! Was that a factory deal or has someone monkeyed with the suspension long before I got the truck?

pic of the rear set up:

Keep in mind, this shot was taken with about a cord of oak firewood in the bed, so it is well compressed.

Sooooo... any ideas on this puzzler?