So far, the plastic valve is doing the trick! Absolutely no heat from the heater box on a test drive when the temp knob is turned all the way down. Now that I think about it, I never opened the valve up, so it’s possible some air is trapped in there from when I replaced it. I’ll post back if there are any problems, but for now I think this is the solution. Thanks for the help!

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Four Seasons has a metal one.  If your interested, its for sale


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

RE plastic heater valves, if it's OEM, it will probably be fine.  If it is aftermarket, probably for an older application, then possibly be prepared to replace it every couple years.

I made the mistake of replacing the original valve on my '88 Firebird as a preventative measure some time in the 2000s.  Since then, I've had to replace the Chinese aftermarket ones every year or two.  They all fail in the exact same way and start to leak.  Fortunately it's pretty easy to replace but I'd gladly pay a couple hundred for a quality billet aluminum unit if it was available.


Lawrenceville, GA

I’m not wild about plastic parts either, but in this installation it’s hard to see, tucked up under the heater ductwork. If it works, I’ll happily live with it!

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Lego?

Thanks for the number and response. I wish I’d thought to do that when I bought one. I guess I should admit while I don’t like plastic, I did have a whole car made out of it once.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I order Four Seasons 74627. It fit perfectly and it definitely totally stops flow when in the off position. I’ll post back after I get to road test to see whether it solves the forever-heat problem.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Miker…the electronic valve was part of my AC conversion/addition and connected to the electronic controller. I don’t know if there is anything like it mechanical. I’ll include a photo of it. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I bought a Newport electric wiper conversion kit and a manual heater-control valve to eliminate the vacuum accessories. I was not pleased about the manual heater-control valve being plastic, but feel better after reading Miker's post. Additionally, I have a shut-off valve at the manifold; if the system leaks, I'll close the valve. Hopefully, the made-in-China shut-off valve won't leak. 

The NAPA looks a lot like mine. I’ve got a short piece of 5/8” garden hose with the fitting to screw on the hose bib. I hooked it up to the valve and turned it on. Closed, it held the 80 psi my house had. That’s sufficient.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ