What the heck is this?

[old Rusty C10]

this has two air lines to it and it goes in between the two sections of the upper hose on the 427?
truck overheated majorly found a pin hole in the heater hose between the block and rad... the hoses here were leaking a little... just trying to figure out what this is going to cost me

[Fatherof3]

It's and oil cooler. They are supposed to go in the lower hose though.

OPPS, I was going by the picture only.

Don't know about air lines

[63 & 64 Bowties]

Interesting. Just a wild guess here from an ex-truck driver:
Could that be an air heater of some kind? The modern air dryers have only been around for about 40 years, so this may be what pre-dated the air dryer. If that's what it is, it would be there to keep the moisture in the air brakes from freezing in winter.
Like I said, just a wild guess.

[old Rusty C10]

Sad thing is none of the guys at Napa know either lol

[Robert1970C20rstbukt]

That's an engine cooler that uses water from the fire pump to cool the engine down if it overheats while pumping water. There is a coil of copper tubing inside, it circulates the water back and forth from the pump. My '69 GMC has one, the copper lines run to a small gate valve near the pump.

[old Rusty C10]

that makes sense.. im going to bypass that for the moment to see if there is any damages to the motor after overheating. Ihave since found the radiator to be leaking