Question about heater hose/vacuum deal thing
 

I have begun the engine swap for my 383 (see sig). While taking off the top half of my TPI engine, I am puzzled by one thing. The coolant hose that exits the psgr side of the T-Body goes into a junction thingy (I know its not too technical). From here it splits into 2 coolant lines that travel back towards the heater core (I believe). The junction thingy has a vacuum line plumbed into the top of it. What is the purpose of this thing? Does it change the route of the coolant flow? Is the vaccum line used as a switch? How will this effect my swap. I had planned on just running a coolant line straight to the heater core and one right back. Any help would be appreciated. Sorry about the bad description. I am at work right now and not sitting in front of the engine.

When the A/C is on ant the temp lever is at its coldest position, this valve routes the water exiting the throttle body back to the radiator. In any other position, it allows the water to go through the heater core. Early models did not have it, and you can do without it, it is supposed to unload the A/C a little bit.

Cheers

Richard

Thanks man! Great to hear it.