I scored a 1976 Jimmy for $200.
Transmission is junk. I got the SBC 400 to run too.
Anyways, on my 75 k10 I plan on a 5.3/4l60e swap. If this thing is an np205 it'll be a bolt up swap (with adapter).
I think its a 205, but not 100%.
The jimmy it came from had a sbc400/th350/and whatever this is