Water pump heater hose size? Straight six 292
 

The formed water pump return hose is 1” ID; and it seems to me the heater hose outlet is 7/8”. The one from the thermostat is 5/8”.
I don’t think there is 7/8” heater hose, is there?

Re: Water pump heater hose size? Straight six 292
 

Gates makes a 7/8" heater hose but I thought the heater hoses were 3/4" and 5/8".

Re: Water pump heater hose size? Straight six 292
 

I thought so too. The water pump outlet for the heater is not 5/8” or 1” Is.

Re: Water pump heater hose size? Straight six 292
 

Oh I think I see what might be the issue. If you look at a National Pipe Thread Reference Chart you'll see that a 3/4" Pipe thread is a tad over 1", they don't go by the normal nut and bolt references most of us are used to.

Re: Water pump heater hose size? Straight six 292
 

Not sure what that has to do with National Pipe Thread sizes.
The water pump connections are cast. Just not sure why they chose a size different than the standard heater hose size. Unless it was intended to match the heater core inlet, which is also larger than 5/8”.
Is there a special hose from the factory that went from the water pump to the heater core?

Re: Water pump heater hose size? Straight six 292
 

Maybe you can find a dual ID heater hose like this as an example - https://www.amazon.com/Gates-18083-H.../dp/B00LGPIWN0
It's hard to tell what your looking for though, no pics. is it in this pic?
https://www.67-72chevytrucks.com/vbo...1&d=1573221521
https://i.ebayimg.com/00/s/OTYwWDEyO...!c!~~60_57.JPG

Re: Water pump heater hose size? Straight six 292
 

Yes - I it is the 63-64 292 version.

Re: Water pump heater hose size? Straight six 292
 

Pics...
Thought I had more; I’ll have to post some later this evening.