The Cab Over Engine (“COE”) configuration dates back to the trucks earliest days, but it mostly faded away until an upsurge in interest in the mid-30s, as it looked modern and was very amenable to streamlined styling. And of course it had a number of benefits, primarily in reducing overall vehicle length, which was always a big issue with car carriers.
Chevrolet did not offer a factory COE at the time (1935) so the job was outsourced to Montpelier Manufacturing, in Montpelier, OH, a long-time builder of truck bodies and vans. The conversion required not only the cab, but also a heavier front axle and steering gear, among other changes. When Chevrolet decided to offer a factory COE in 1938 or 1939, they contracted with Montpelier to help design it.
Here’s a brochure for the Montpelier conversion, which was available on a variety of wheelbase chassis as well as with van bodies. A sleeper cab was also available.
This is the new “factory” COE, developed with technical assistance by Montpelier. Chevrolet was a bit behind the game, as Dodge, Ford and International already offered factory COEs.
There’s a bit of a question as to whether these first came out in 1938 or 1939; best bet is mid-year 1938.
In 1941, Chevy trucks got a restyle, including the COE. I snagged one of these some years back, and its whole story is here: Truckstop Classic: 1941 Chevrolet COE: Streamlining Arrives Down On The Farm