The last inline Jimmy would've been '59, the '60- about'67/68's had the 305 V-6.
A side thought though, anyone consider the new Atlas inline 6 from the Trailblazer/Envoy? My parents have an Envoy, and that engine looks like it would fit ok. I heard a rumor that GM was considering a crate motor version with a stand alone computor like the Ramjet engines.
I should mention that the step vans used the 270 for a few years until the 230 Chevy engine came out.
