From 1977-1991 (K30 from 1977-1986, V30 in 1987 and 1988, and V3500 from 1989-1991 I believe).
Chevy's were 30's and GMC's were 3500's. I'm not real sure exactly what year both were designated 3500's.
The first few years they were available with either a straight six or a small block, they weren't available with big blocks until the early '80s though, not sure of the year. Also not sure what the first year you could get a diesel in one.
I know '81 had BBC's as I've seen a few of them. '82 also had them for sure as I've owned one before.
They all had Dana 60 fronts, the DRWs have Dana 70 rears and the SRWs have 14bff's.
DRW's also ran 14FF's. These were a narrow axle. Trucks that ran a narrow 14FF didn't have the fleetside beds with fiberglass fenders. These trucks were generally trucks that were meant for flatbeds or utility beds, etc. They kept the rear tire widths tucked under the beds and not protruding out so far like the D70HD.
You could get them with either a SM465/NP205 or a TH400/NP205 (4L80E/NP205 in 19991).
Don't forget the 350/203 and 400/203 combo. '77 trucks can have these if they didn't opt for the 465/205 setup. I'm also not real sure exactly what year the 400 tranny began in these K-series trucks but I have seen them in '79 for sure. All '80 trucks had the 205 t-cases and tranny options were 400 or 465 only. I've seen a '79 K3500 with the 400/203 combo, too.
Martin