reinstalling every thing after valve job and this hose about 3/8 OD and 3 feet long is laughing at me for not labeling it. It has what looks like a six sided connection on one end.

 

That MIGHT be, I repeat might, be the hose that runs from the LH side spout on the thermostat housing TO one of the spouts on the coolant reservoir at the back LH corner of the engine bay near the LH side of the valve body... If the reservoir isn't in place because you are still working on things,,, yeah, it wouldn't be so clear...

 

I have that one installed

I suspect I may have just used this to drain the coolant tank and then left it in the engine bay.

 

I see, I see...
Oh and,,, before I meant "throttle body". My bad.