Big block heater hose question!

[hgger69]

Hi,
I´m going to install the heater box hoses on my ZL-1 build but I´m not sure which one goes where?

The ASM shows this, which looks nice but is it correct?



I did some search on the net and found this thread that John Z commentated the same question with the opposite place for the hoses:

The hose from the outlet fitting (manifold) always goes to the bottom heater core fitting, and the hose from the inlet fitting (water pump) always goes to the top core fitting; that way the core is always full of coolant and there's no "gurgling" sounds from air bubbles audible from inside the car.

 The upper hose from the core back to the water pump is slightly larger in diameter so it always has lower pressure (carrying the same volume of coolant) to maintain steady coolant flow at low rpm so constant temperature control adjustments by the customer aren't required.

What du you original guys say about this topic? 

[Everett#2390]

Supply hose to core is 5/8 inch from intake manifold.
Return hose is 3/4 inch to water pump nipple.

[hgger69]

Supply hose to core is 5/8 inch from intake manifold.
Return hose is 3/4 inch to water pump nipple.

Thanx Everett, but this means that the ASM is completely wrong then??

[cook_dw]

Not the first time the assembly manual was wrong.

[Mike S]

 I looked at my 67 L35 and the water pump hose attaches to the top pipe on the heater box and intake manifold to the bottom pipe. This matches the 67 AIM.
Being the heater box has two different size pipes and the engine has two different size nipples, just match the two.

Mike

[hgger69]

Not the first time the assembly manual was wrong.

Great picture, thanks!

[hgger69]

I looked at my 67 L35 and the water pump hose attaches to the top pipe on the heater box and intake manifold to the bottom pipe. This matches the 67 AIM.
Being the heater box has two different size pipes and the engine has two different size nipples, just match the two.

Mike

The heater core does have two different sizes on the tubing but I don´t think there are two different sizes of the nipples on a 69 BBC but while I built my engine myself I could be wrong! 
The picture in my first post is from the 1969 ASM, or AIM, and apparently it´s wrong then! 
Many thanks for your help in this matter, guys!

[Kelley W King]

Haken, I remember that picture of your pump to intake hose being a little deformed. Mine is too now. I could not find a formed hose except the 90 degree one.

[hgger69]

Haken, I remember that picture of your pump to intake hose being a little deformed. Mine is too now. I could not find a formed hose except the 90 degree one.

Kelley, it’s not deformed att all but there no molded hose for this application, just a normal hose that’s slightly bent to connect the pump and manifold!