Thermastat housing

juggernaught

Need to have my memory "jogged". When I disassembled my "76/78 amc 360, I believe that I have a 1/2" threaded port on the back of the housing. Cannot remember for the life of me what it operated or if it is really necessary to reuse. I have been looking at replacing the housing and most new ones do not have this connection. I will be installing a holley truck avenger carb. on a performer intake.

jeep_man_401

Controlled vacuum advance via coolant temp. Had a threaded 3 port temp controlled valve in the port. I run a locked dissy with MSD timing computer so mine is plugged.

Mudrat

That's where I fitted my mechanical temp gauge :wink:

juggernaught

So is that port hooked up to my stock dist. only, because the dist. is a vacuum advance style?

tufcj

The thermostat switch stopped the vacuum advance until the engine warmed up for emissions reasons. Unless you want that totally stock look, just plug the hole and run the vacuum advance directly to the ported vacuum source on the side of the carb. Bob tufcj

msalaba

It's part of the emmission control system. iirc, it locked out the vac advance untill the engine warmed up to lower emmissions and help the engine warm up faster. Most of the time this switch dies and is bypassed. If you are going for a factory build, a TSM will have plenty of vac diagrams. The Cali smog vehicles had a lot more vacuum crap on it than the 49 state vehicles. Otherwise, you can plug the hole where the switch is and run your dist off ported vac on the carb. (port on the carb that gets its vac signal just above the throttle plates)

juggernaught

Thanks guys. May just look at deleting the port. Will check out the set-upwhen I get home.

jeep_man_401

Mudrat

That's where I fitted my mechanical temp gauge

But you're not reading actual engine temp there, what happens if your thermostat gets stuck...I always put mine before the thermostat...any hole will do. :mrgreen:

msalaba

jeep_man_401 wrote
Mudrat

That's where I fitted my mechanical temp gauge

"

But you're not reading actual engine temp there, what happens if your thermostat gets stuck...I always put mine before the thermostat...any hole will do. :mrgreen:

Good catch. I was going to say something in my previous post but CRS got the best of me #-o

Too bad AMC didn't put a port in the head like most chebby's... 🙁: