The heater used in the Chevy 1.5 ton truck was a simplified version of the available model. All the baffles were stamped, no chrome.
The 'triangle' type Harrison heater I am searching about is shown in the photos in the posts above. It was used (and can be documented) in GMC 2.5 ton trucks as part of the 'arctic' kit'. Since it never took in outside air, I don't think its the one mentioned in the above post.
None of the information in the book was not of any use, it stopped at 1933. The 'War years' were WWI.
The article was neat, but otherwise uninformative.
What I can get from period manuals is the model number for the post war 1948+ heater was Harrison Heater model number H441A. Some have suggested that 441 is April, 1941 as a possible combination. But I have no official reference of that... just people guessing.
The heater itself is GMC-3117868. This is taken directly from the installation manual provided with the heater.
