Topic: Autolite 4100 HiPo Carburetor Part Question?

[Morsel]

I'm wondering what the name of this brass flathead plug screw is called (see attached image)? If I knew the name of it, I would probably have an easier time searching for a new one, but if anyone knows a source let me know, need one for my carburetor.

Thanks as always,

Jason

[jwc66k]

It's a "plug", possibly including "vacuum advance" in it's description. What are the numbers/letters on the left front mounting foot?
Jimi

[Morsel]

It's a "plug", possibly including "vacuum advance" in it's description. What are the numbers/letters on the left front mounting foot?
Jimi

Hey Jim,

It?s a 6Z F carb for my 66 HiPo automatic car.

Jason

[Dan Case]

What did Ford call the plug? I have no idea. It seals the spark advance vacuum port that is not required for engines with fully mechanical ignition advance designs. (It is very different than the 1963-64 part used in carburetors for 427 and HP289 engines.) I spent most of a day digging through Ford parts books and training manuals one day in 2019 and never found an exploded view drawing or parts list line item for it in the 1964.5-67 production years. (I never found a Ford number of any kind for the 1963-64 version either.)

I made these drawings for somebody wanting to have some accurate copies made.



I have seen modern commercial replacements for sale but they lack the fine details of the unmolested originals I got to borrow and use for measurement work.

The flat faced straight threaded tapered seat for sealing plug went into use near the end of C3OF-AJ carburetor production in 1964 and was in April 1964 in C4OF-AL carburetors. The earliest carburetor assembly date code I have recorded using the flat face SAE thread plug is the last week of January 1964.

[Dan Case]

The brass pipe thread part was a Ford-Holley piece for several street and race 427 Ford carburetors before September 1964. Circa September 1964 Holley changed to a zinc plated steel version for 427 Ford carburetors that used a plug and the R-3259/3259-1 carburetors for Shelby.  When the C3OF-AB carburetor was introduced with 289 High Performance engines in March 1963 they also used the brass pipe threaded part. The use of C3OF-AB carburetors ended circa Mid may 1963 and C3OF-AJ carburetors were used until at least mid May 1964.

[Morsel]

The brass pipe thread part was a Ford-Holley piece for several street and race 427 Ford carburetors before September 1964. Circa September 1964 Holley changed to a zinc plated steel version for 427 Ford carburetors that used a plug and the R-3259/3259-1 carburetors for Shelby.  When the C3OF-AB carburetor was introduced with 289 High Performance engines in March 1963 they also used the brass pipe threaded part. The use of C3OF-AB carburetors ended circa Mid may 1963 and C3OF-AJ carburetors were used until at least late May 1964.

Thanks for the info Dan, very helpful and yeah, can't seem to find them anywhere online. Luckily someone had a couple and is sending me one, so at least I got one coming for my carb

Thanks,

Jason

[Dan Case]

Thanks for the info Dan, very helpful and yeah, can't seem to find them anywhere online. Luckily someone had a couple and is sending me one, so at least I got one coming for my carb

Thanks,

Jason

You are welcome.