Aftermarket Vortec 5.7 air-gap manifold and coolant hoses

[BlazinBlazer1994]

Good evening all,
I am approaching a point (1994 full size Blazer) where I'm working on the cooling system. I've swapped the TBI motor to a rebuilt 5.7 Vortec. I have installed the below intake manifold, and a 1998 water pump. I have determined that port "B" on the water pump is the return port from the heater core on a stock Vortec 5.7, and I can run that hose on my Blazer. I can't determine after hours of looking online what port "A" on the water pump is for. I think I may need a bypass hose but which port on the manifold? Also, how do I connect the hot water feed to my heater core? If there's a diagram or a thread on this forum anyone can point me to I would appreciate it. I do have a port on my radiator just under the cap that was originally for the heater core return.

 

[Schurkey]

1. I wouldn't touch an air-gap manifold if you live in an area with cold temperatures.

2. "A" on the manifold is the heater supply, unless there's another port near the right rear corner. You could connect the heater core outlet to "A" or to "B" on the water pump, but I'd have it go to the radiator like it is now.

3. Pretty-sure "C" on the manifold is for the coolant bypass leading to either "A" or "B" on the water pump, whichever is easiest to connect to.

In other words, both "A" and "C" on the intake are outlets, and both "A" and "B" on the water pump are inlets. Connect 'em however it's most convenient.

 

[Xtreme1]

Hello....I googled 5.7L Vortec coolant flow and found something contray to your attachment points.
* Tube "B" you have marked is for the short "bypass hose" to the lower front port of the intake manifold you have marked as point "C".
* Tube "A" you have marked is for the "Return Line from the heater".
* For coolant flow (hot) to the heater, you need to install a nipple into the top front passenger side port you show on the intake manifold you show as point "A".
****REMEMBER....There isn't a "which is easier"....it's a "WHICH IS CORRECT"!!! You'll keep your engine much longer that way!
Also be aware that your water pump is a "REVERSE ROTATION" (CCW), so make sure you're belt routing is in the proper direction!!!
....and GOOD LUCK!

 

[Schurkey]

****REMEMBER....There isn't a "which is easier"....it's a "WHICH IS CORRECT"!!! You'll keep your engine much longer that way!

Ehhh...both intake manifold ports are coolant "outlets". Both water pump tubes are coolant "inlets".

I don't think it makes a bit of difference which outlet eventually ends up at which inlet. They're functionally identical as far as I know. A person could verify that neither one is restricted or somehow "different" from the other.

GM may have selected one outlet to go with a specific inlet...but it was likely selected because it was the most convenient for them.