Grit dog wrote:
The early “heavy halfs” were made to skirt new emissions regs in the late 70s. Side benefit was a little more spring capacity in a half ton.
GMT 400s actually got a heavier axle. And IMO the gmt800 1500hd was too close to the new 2500hd and not very popular.
I've got a 2000 model year GMT800 "2500" sitting out back rusting away. No "HD." Standard cab, 8' bed. Semi-floating 14-bolt axle with 8-bolt hubs. 8600 GVWR.
The 1500HD was strictly a crew cab 6.5' bed configuration as I recall. If you wanted something different you bought a 2500.
I think it was either an answer to Ford's F150HD/F250-non-Super-Duty with the 7-bolt hubs, or a marketing thing for folks in HOAs with 5th wheels that needed capable trucks with GVWRs of <10,000.
You are right they were never very popular.