truck and car chassis and dashes are enough different I'd expect problems someplace trying to mix them, get the car harness .... someplace like https://www.chevsofthe40s.com/ or maybe https://www.fillingstation.com/ or even http://www.truckandcarshop.com/ should have stock stuff

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics