The pre-84 4wd trucks have the same shock mount sizes as the 2wd trucks. Since the 2wd's are spring under and the mounting plate is under the spring, you have the correct mounting surface (flat) to use it ontop of the 4wd springs.
Here's a pic of what I'm talking about (with a broken spring pack, lol!):
[Linked Image]

I'm currently using shocks spec'd for an 83 4wd with 3" lift.

1986 Pickup extracab longbed "Woody edition"
SAS - 33's, 5.29's, lockright rear.

02 IS300 SportCross - my "DD"
94 2wd v6 extracab
04 Outback Wagon- wife's/family car