I'm in the middle of getting my new to me cab ready to put on my 64 gmc. i have the deluxe heater in the truck now. My question is has any one ever put a heater from a differant car/truck in their truck to remove the "bread box" under the hood and clean up the firewall?
All About Heaters Here ya go... lot's of good data: http://67-72chevytrucks.com/vboard/showthread.php?t=488618
A few years ago I built a 49 Studebaker pickup street rod and installed an under-the-dash universal "hot rod heater". The heater was 12V, 2 speed, and had a built in motor and core. It worked great! I may do the same in my 66 C10 that I'm currently building. I want to clean up the firewall and will not have the $ to install a heat/air unit for a while. Speedway Motors, Inc. sells them for $140. You might find one cheaper with an internet search. The one in the Studebaker cost me less than $100.
But What About a Defroster ? Defroster? That's the issue I see with a "Hot Rod Heater" (I bought one for my old '27 Ford Roadster, doesn't need a defroster). A closed cab vehicle needs a defroster or else the windshield will be fogging over and you'll be wiping it down with a rag. A lot of the severity of the problem will be related to where you live. Live in a humid area then it's a big deal. Arid area, not so big a deal.
The one I bought for my Studebaker had a defroster port that could be used or blocked-off, as well as a door on the front. I hooked up the defroster and it worked fine. However, I bought that heater in 1997 and they're probably cheap Chinese crap now w/o defrost capabilities.
Well i've given up. for now i'm just goin to put the factory heater back in the cab. although i did talk to my cousin and he said to find a heater out of a 73-87 chevy that did not have ac. He just reworked one in a c60 and he thought it would work if i can find one. But for now ill just keep the factory one.