[Mike C]

If memory serves, the 4 wheel drive early trucks and Blazers are 40" while the 2 wheel drive are something like 42 3/4. Approximately. I sold my 2x4 so can't measure for sure.

Perch width can be an issue as well. My jimmy and the 2x4 Longhorn parts truck I had both had 2 1/2" wide springs but the (2) 2500 trucks I had with leafs were both 2 1/4" wide.

I built a jig off my original rear to re-do the perches on my 14 bolt for the Jimmy. I cut the original perches off with the plasma and TIG'd them back. I used the original 12 bolt shock mounts on the 14 as I like them better, better tucked up.