Technical Holley carb missing a vacuum fitting

Holley 4160, carb came with, but not on the car. Decided to rebuild/renew because the accel. pump wasn't moving at all. Found the power valve gasket was wrong, also. There was no stub or plug in the vacuum port.
Q- what fits in there? it doesn't look like NPT pipe thread. I can't find a fitting on-line anywhere. Is it a threaded fitting with a gasket? Don't know if you can see in the pic but 3-4 threads in are buggered up some. I was told that this is the best place to run the dist. vac line from. Do you agree?

 

Is it drilled out from Holley?

 

Is this a Ford metering block? That would be for the early vacuumatic (sp) distributors (not vacuum advance) If it is a Holley metering block than that is manifold vacuum and will operate a vacuum advance.
The top of the metering block will have some numbers.
Johnny Gee, I have seen many from Holley that were not drilled, but they were not threaded either. They just gathered dirt.

 

Yea, and threaded. In your pic it appears to be a flare type fitting.

 

That is 1/8 NPT ( national pipe thread ) female thread . It is a very common fitting available at any chain hardware store . Just get 1/8 NPT Male to what ever hose you decide to use . Small for the vacuum advance . I’m thinkin 5/32. This comment will draw lots of attention GM= full vacuum below the throttle plate , Ford= ported vacuum above the throttle plate . If you are using on a GM car I would plug that port and use a “ nipple “ provided for vacuum advance on the throttle plate . Up to you get a proper fitting and try both ports to see which is best for your needs . Good Luck , it also looks like you may need a tap to clean out or chase the thread in the carb body . If you do this just remember it’s taper thread and you are just chasing the thread , you go to deep and the fitting will never seat correctly . A drop of blue lock tite is the answer to seal the threads no Teflon tape here . Teflon will end up somewhere in your carb that God can not retrieve .

 

THANKS. That's what I needed to know. I have 1/8''NPT nipples lying around here. Just wanted to make sure before I tried to screw one into that aluminum thread. Have a tap & blue loc-tite too.
Noticed the on-line debates on which port to use, so confused. BTW it's going on a 350 SBC.

 

You can buy brass nipples with hose barb on them, but I wouldn't use loctite. Thread sealer, maybe.

 

The fitting that the factory installed on my 365 hp motor was restricted. Available from Long Island Corvette Supply. Been a long time but I think the hole was like 1/16-1/8th. Could fill one with JB weld and drill it I guess. Don't know if the smaller horse motors had the same fitting or not. D

 

https://www.holley.com/products/fue...gs_fuel_lines_and_gauges/fittings/parts/26-59

 

Restricting the flow of "zero" vacuum (returning make up air) will keep vacuum advance pot from slamming back would be the only advantage.

 

I've found best results on my Fords by connecting the vacuum advance directly to manifold vacuum, usually on the manifold. That port on the Holley is 'ported' vacuum; no vacuum with the throttle plates closed at idle, manifold vacuum after they open.

 

JB Weld was my plan B.

 

Be a lot cleaner to just plug it with a brass 1/8" NPT pipe plug.

 

I meant if I couldn't clean up those threads well enough.

 

JB Weld ?

 

I chased the threads with a tap, cleaned up nice , and have a fitting coming from Summit. Now for the ignition....

 

Out of curiosity, is your Maico a 501

 

No. I had a 400 in '74, and a pair of 250's in '75 & '76 . still have the 250's

 

Back when I dreamed of a Rokon