KLhansen you are correct it was plumbed into the coolant system and the big part on the firewall was plumbed into the vacuum port on the back of the intake. I didn't get pictures of it but there is also probably a six inch tall block the carburetor is mounted on. On the side of that was facing the pump there is a small gear that drives some kind of actuator that must have got the system started. I ran patent numbers and they did come back to the company that built the truck out but never a specific system. It was built out by American Fire apparatus co. Unfortunately they were bought out and eventually closed. I really appreciate the help its had me scratching what little hair I had on my head out lol.
