Thread size intake manifold vacuum port

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Ronbo
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Thread size intake manifold vacuum port

Post #1 by Ronbo » Wed Oct 21, 2015 9:56 pm

High all. I have the 250 head and was wondering what the thread size is for the vacuum fitting that sits behind the carb pad. I have a fitting in there but it won't seal up, even with teflon tape. Its giving me fits :bang: :bang: :) so any inf will be greatly appreciated. Thanks, Ron.
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

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bubba22349
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Re: Thread size intake manifold vacuum port

Post #2 by bubba22349 » Wed Oct 21, 2015 10:10 pm

It's a US - NPT (National Pipe Thread) and I think it's 3/8 or 1/2 inch if your using a metric pipe thread then that's why doesn't fit. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

Ronbo
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Posts: 965
Joined: Fri Nov 08, 2002 8:56 am
Location: Sierra Vista, AZ

Re: Thread size intake manifold vacuum port

Post #3 by Ronbo » Thu Oct 22, 2015 8:45 pm

Thanks for the reply Bubba. The one I'm using is a 3/8 NPT and I dont get it. :hmmm: I tried some thread grease from ACE and that didnt work, didnt think it would. The aluminum threads cut the heck out of the pipe tape and you can't find adapters/fittings anywhere anymore.

Ron
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

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bubba22349
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Location: Flagstaff, Az. 86005 near the old Route 66

Re: Thread size intake manifold vacuum port

Post #4 by bubba22349 » Thu Oct 22, 2015 11:57 pm

Every so often you will find a fitting that fits a bit loose because they cut the threads a little too deep you could try another one. You can also use some of the Permatex gasket sealer in hardening type if its real loose or the non hardening type if it's at least snug, or some of the Teflon pipe dope that is used for water and gas pipe. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

Ronbo
Registered User
Posts: 965
Joined: Fri Nov 08, 2002 8:56 am
Location: Sierra Vista, AZ

Re: Thread size intake manifold vacuum port

Post #5 by Ronbo » Fri Oct 23, 2015 6:43 am

Will do. I forsee a long weekend ahead. The thing snugs up just fine just wont seal. Its actually made up of three fittings so I'll try a plug first then add pieces in as I go, maybe the brass cracked on the main piece. MTF

Ron
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

Ronbo
Registered User
Posts: 965
Joined: Fri Nov 08, 2002 8:56 am
Location: Sierra Vista, AZ

Re: Thread size intake manifold vacuum port

Post #6 by Ronbo » Fri Oct 23, 2015 9:21 pm

Bubba you were spot on. I went stopped on the way home and picked up a new fitting and voila, tight as a drum!

Still wont idle though, it's going to be a long weekend :(
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

User avatar
bubba22349
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Posts: 8243
Joined: Sun Jan 03, 2010 4:46 pm
Location: Flagstaff, Az. 86005 near the old Route 66

Re: Thread size intake manifold vacuum port

Post #7 by bubba22349 » Sat Oct 24, 2015 2:15 am

:beer: congrats on getting the fitting in a little better. Are you chasing more vacuum leaks? :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

Ronbo
Registered User
Posts: 965
Joined: Fri Nov 08, 2002 8:56 am
Location: Sierra Vista, AZ

Re: Thread size intake manifold vacuum port

Post #8 by Ronbo » Sat Oct 24, 2015 3:30 pm

I think I am :?
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

User avatar
bubba22349
Global Moderator
Posts: 8243
Joined: Sun Jan 03, 2010 4:46 pm
Location: Flagstaff, Az. 86005 near the old Route 66

Re: Thread size intake manifold vacuum port

Post #9 by bubba22349 » Sat Oct 24, 2015 6:59 pm

If you still have good hearing you can use some small rubber Vacuume hose 1/4 to 3/8 inch and listen at the different places along the carb base and intake manifold. And you can also use smoke (about the cleanest way), spray carb cleaner, and a half dozen other ways too to find those Vacuume leaks. Best of luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

User avatar
bubba22349
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Posts: 8243
Joined: Sun Jan 03, 2010 4:46 pm
Location: Flagstaff, Az. 86005 near the old Route 66

Re: Thread size intake manifold vacuum port

Post #10 by bubba22349 » Sat Nov 28, 2015 4:06 pm

Hi Ronbo, How is your project going did you get it running good yet?
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

Ronbo
Registered User
Posts: 965
Joined: Fri Nov 08, 2002 8:56 am
Location: Sierra Vista, AZ

Re: Thread size intake manifold vacuum port

Post #11 by Ronbo » Fri Jan 15, 2016 1:53 pm

Bubba, sorry I didnt hit you back with a follow up. Yes the threads on the fitting I had were cheesed so I bought one from Lowes and voila! Tighenet right up. As you know its still not running "right". I'll be chasing a vacuum leak tonight.

Ron
2013 F-150 FX4 5.0
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

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