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Old 03-30-2021, 07:03 PM   #1
jakesblazer
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holley 4412 too big for my 250?

72 blazer 2wd inline 6. It came with a offy 4 barrel intake and a 4412 Holley 2 barrel carb. The carb was messed up so I went to the local you pull it yard and got a cast 1 barrel intake and a monojet. Ran great. By buddy is making me go back to the old setup. Will it like it? Motor is built up pretty good .30 over, cam, flat pistons, headders. thanks yall!
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Old 04-02-2021, 09:47 AM   #2
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Re: holley 4412 too big for my 250?

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Originally Posted by jakesblazer View Post
72 blazer 2wd inline 6. It came with a offy 4 barrel intake and a 4412 Holley 2 barrel carb. The carb was messed up so I went to the local you pull it yard and got a cast 1 barrel intake and a monojet. Ran great. By buddy is making me go back to the old setup. Will it like it? Motor is built up pretty good .30 over, cam, flat pistons, headders. thanks yall!
I guess I would have had the Holley rebuilt instead of buying the original intake and carb. Your motor with should run nice with the 2 barrel. If you go to the top of the original page and click on search, put in tricked out sixes or 250/292 with 4 barrel and you will get all kinds of responses.
I just bought a Offenhauser intake for my stock 292 and a Holley 550 CFM carb to install. I have turned the carb so that it faces the front of the truck and plan on installing a cable linkage, I'll post a picture of it for you. Good luck with your venture.
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Old 04-02-2021, 03:29 PM   #3
RichardJ
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Re: holley 4412 too big for my 250?

4412 Holley 2 barrel carb is a BIG 2bbl. 500 CFM.

Depending on vehicle weight and gearing, I would expect drivability issues with that big of a 2 bbl. Even a 650 CFM 4 bbl would have better street manors, because of much smaller primaries.

>>By buddy is making me go back to the old setup.<<

Tell you buddy to go soak his head.
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Old 04-02-2021, 04:09 PM   #4
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Re: holley 4412 too big for my 250?

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4412 Holley 2 barrel carb is a BIG 2bbl. 500 CFM.

Depending on vehicle weight and gearing, I would expect drivability issues with that big of a 2 bbl. Even a 650 CFM 4 bbl would have better street manors, because of much smaller primaries.

>>By buddy is making me go back to the old setup.<<

Tell you buddy to go soak his head.
Agreed, on all counts.

I'd put on a carb with progressive linkage, a la Q-Jet. It would only open the secondaries to the demand.
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Old 04-03-2021, 03:22 AM   #5
'68OrangeSunshine
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Re: holley 4412 too big for my 250?

I used to run the Holley 4160 R8007, a 390 CFM 4 bbl that was recommended for L6s. After 25 years and 250,000 miles, after an engine rebuild, it was shot. I went with an Edelbrock 1404, 500 CFM on a 292 bored .030 over [=296 CI]. I like the Performer.
Old Holleys required a fresh power valve after every backfire. Got to be annoying.
I have the same Offy intake.
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Old 04-03-2021, 11:26 AM   #6
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Re: holley 4412 too big for my 250?

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I used to run the Holley 4160 R8007, a 390 CFM 4 bbl that was recommended for L6s. After 25 years and 250,000 miles, after an engine rebuild, it was shot. I went with an Edelbrock 1404, 500 CFM on a 292 bored .030 over [=296 CI]. I like the Performer.
Old Holleys required a fresh power valve after every backfire. Got to be annoying.
I have the same Offy intake.
Either of those are just as good, and probably easier than finding a Q-J manifold, too!
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Old 04-03-2021, 03:18 PM   #7
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Re: holley 4412 too big for my 250?

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Either of those are just as good, and probably easier than finding a Q-J manifold, too!
GM of Brazil made an L6 Quadrajet manifold. They pump pure cane alcohol there.* Don't know any Brazillians though.

* 191 Rum, anyone?
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Old 04-03-2021, 12:02 PM   #8
geezer#99
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Re: holley 4412 too big for my 250?

Everybody should keep in mind that if you flow rate a 2bbl the same as a 4bbl that the cfm of the 2 bbl is about 2/3 of the equivalent size 4 bbl.
The 500 cfm 4412 flows about 350 cfm compared to a 500 cfm 4bbl.
And if you want a quadrajet just use a spreadbore adaptor that bolts to the plate on an offy.
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Old 04-03-2021, 03:29 PM   #9
'68OrangeSunshine
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Re: holley 4412 too big for my 250?

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Everybody should keep in mind that if you flow rate a 2bbl the same as a 4bbl that the cfm of the 2 bbl is about 2/3 of the equivalent size 4 bbl.
The 500 cfm 4412 flows about 350 cfm compared to a 500 cfm 4bbl.
And if you want a quadrajet just use a spreadbore adaptor that bolts to the plate on an offy.
The Edelbrock Performer [clone of late Carter AFB] is a vacuum secondary type. So only as much fuel/air mixture as you need can flow. Q-Jet operates on a similar principle, I'm told.
Interesting concept -- to bolt a spreadbore adapter onto the Offenhauser 5416 and run the Quadrajet. Like to see pix of that.
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