Just picked up my first Chevy truck of this vintage - 1984 K20 5.7 w/ a 350 crate motor. 4 spd manual (1-3 plus L - that's the 4 speed I assume...)
Trailered it home and have started to make my initial diagnoses. At the moment, my priority is to get it drivable so I can use the truck this winter.
It runs strong, although it has an oil leak and needs a choke adjustment. It will need a compete brake job (it had no brakes, so in attempting to bleed the system I found the bleeder bolts completely rusted and not serviceable). So that's my first project. Along with changing all the fluids.
Here's a pic from the trip home: