Hello to all.
I recently purchased a 1953 GMC 450 Fire Truck with an American Fire Apparatus body. Here are a few photos of the truck for reference 1953 GMC 450 Fire Truck

The truck is outfitted with a Barton front pump (not sure of the model yet) and a mid mount gear driven booster pump.

Since the truck did not come with any manuals related to the pumping systems I am slowly charting the pumping lines and engine bay components related to the pumps. I think I got most things figured out but I still am not sure of the true function of the "surge/cooling" box which is mounted above the engine.

Would anyone have any ideas on how I might be able to find any information related to the engine bay components?

I also have a series of reference photos of the engine bay I can post if that would be helpful.

Thanks for the help- Bob