Heater Dilemma

[1GMC4x4]

Ok call me dumb but I cant figure this whole heater core thing out. I transplanted a 1994 454 TBI into a 69 GMC and I cannot figure out which lines go where. I have one coolant line in front of the intake manifold, at the water pump and a plug in the back of the intake manifold. I know this must be as simple as it gets but I truly dont know.


Thanks
and go easy on me.

[trkklr77]

double fail on the pump to intake, that pair of fitting is suposed to connect so the pump isnt cavitating when the tstat is closed.

there is a blank boss on the water pup that is usually tapped and that is what would typicaly run to the core, the core on the newer trun would run right back to the radiator. on my 71 i ran it back to the intake, but you cant.

the brass plug in the rear should be a vacume port and not water.

there shoudl also be temp sensor ports on the sides of the heads, well at least older bbc's

[1GMC4x4]

so correct me if I'm wrong; I cannot run the heater core with the setup I have now, and I need a water pump with two ports to get the input?? for the heater core? and the return goes to the radiator?


Thanks!

[trkklr77]

you dont need the pump with 2 ports but that is how it is typicaly done. if you had a port on the intake that would help but i dont see one.

[mudskipper4x4]

Im not that familiar with the tbi 454's but the tbi 350's have a port coming out of the intake right by the distributor.

Maybe the 454's are the same and yours is just plugged?

And like was said before the other line went from the core to the rad directly.

And I don't think you will have much luck with it set up the way it is now.

[HAPPYJOHN]

Originally Posted by trkklr77

double fail on the pump to intake, that pair of fitting is suposed to connect so the pump isnt cavitating when the tstat is closed.

Could he not, in theory, run the cavitation line throught the core?
or would it not flow when t-stat opens? (pardon my ignorance)

[trkklr77]

sorry for getting back to this so late.

but yes he CAN run it like that/he did, but not the way he did it. get some decent fittings and fix the kinks, but im sure you already have and the pointles to spell out for you by now.