I wrote:

>It hooks two hoses together.  It hooks two more hoses together.  It
>physically supports both hoses as they cross the firewall.  I
>*believe* nylon hose barbs would fit the bill.
>
>And it makes a restricted bleeder connection with a shutoff valve
>from I forget where to I forget which one of the hoses.  Might need
>to drill one of the barbs and screw/bolt in a small valve and nipple
>for the bleed. If you didn't want to mess with an actual
>valve,  just inserting a small nipple and pinching off the little
>bleed hose ought to take care of it.  The original had/has a little
>folded sheet metal gizmo inside the small hose nipple.  Conceivably
>that might be a bubble separator.  But the whole thing only comes
>into play when you're bleeding the system.

Correction:  The bleeder actually connects the two big hoses
together.  In Bentley 19.9 they show a setup where there are two
nipples coming from the big hoses/pipes, with a separate bleeder
fitting with three nipples -- two for the big hoses and a third going
to the heater crossover pipe.  There's a decent schematic of this
arrangement on 19.10.  This and 19.19 show the always-open connection
to the heater crossover to be to the lower big hose, the one that
carries flow from the thermostat to the radiator.

In production they apparently changed to the existing setup, where
the big hoses are divided by the big bulkhead fitting which has an
internal bleed connection between the two sections.  This is not
illustrated in Bentley, but I'll send you an illustration.  The
curious thing is that in the revised setup the illustration shows the
heater connection coming vertically off the top of the fitting, *and
apparently connecting to the (upper) return hose from the radiator
back to the thermostat.*

Now my recollection of my own such device on Dutiful Passage was that
the heater nipple came out horizontally, but still from the upper
hose -- a better lead to the heater pipe but functionally the same.

I still say you could fake it functionally without great trouble.

Yours,
David