Single or Dual Clifford Intake?

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dr johnny fever
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Single or Dual Clifford Intake?

Post #1 by dr johnny fever » Wed May 16, 2018 8:30 pm

I'm trying to add some get-up-and-go to my 86 F150. I was considering swapping the motor but even thought I know it's more $ I just love the straight 6.

I just got bought some EFI headers and as soon as I get them installed my next project is to upgrade the carb/intake. The old feedback carb was kicking my butt so I finally gave up and removed the computer and EFI stuff and switched to an HEI dizzy and manual choke 1B Carther YF on the stock intake.

I was originally looking at the Offy C but I like the fact that the Clifford has the internal water jacket (one less thing to have to piece together) so now it comes down to single or dual intake. How much more bang do you get for the (considerable) buck for the dual? Do you think there's a noticeable difference in performance? Thanks!
1986 F150 4X4

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THE FRENCHTOWN FLYER
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Re: Single or Dual Clifford Intake?

Post #2 by THE FRENCHTOWN FLYER » Wed May 16, 2018 10:36 pm

Not much difference in a "C": vs a dual plane, but I do like the dual carb Clifford for both looks and better fuel distribution. Going from a 1V to a 4V is huge. Going from a (1) 4V to a dual carb intake is not so big on a relatively stock engine.
Last edited by THE FRENCHTOWN FLYER on Wed May 16, 2018 10:40 pm, edited 1 time in total.
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pmuller9
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Re: Single or Dual Clifford Intake?

Post #3 by pmuller9 » Wed May 16, 2018 10:37 pm

The Clifford single intake requires a carburetor adapter plate ($59) so you still end up with a 2 piece intake.

The next biggest performance gain after the intake manifold and carburetor will be a performance camshaft.
Is that something you would consider?

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dr johnny fever
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Re: Single or Dual Clifford Intake?

Post #4 by dr johnny fever » Sun May 20, 2018 8:17 am

Thanks FTF, that’s what I need to know. I’m going to buy the single intake. I’ve been reading the forum and and thinking about putting the four barrel Edelbrock 500 (model 1403) on it. Is that a good choice?

Thanks, pmuller9. I noticed it was also 2 piece, but I can just get the adapter from them and don’t have to do any research or figure out what works best, etc.
1986 F150 4X4

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dr johnny fever
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Re: Single or Dual Clifford Intake?

Post #5 by dr johnny fever » Sun May 20, 2018 1:09 pm

pmuller9 wrote:The next biggest performance gain after the intake manifold and carburetor will be a performance camshaft.
Is that something you would consider?


Yes, but I’d like to try the chebby rockers first. once I get the EFI exhaust manifold, Clifford intake + (whichever) new carb, and the 1.7 rockers I think that’ll give me plenty of pep until it’s time to rebuild the motor. It has 350k in it, so it’ll be there at some point.
1986 F150 4X4

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Re: Single or Dual Clifford Intake?

Post #6 by pmuller9 » Sun May 20, 2018 8:58 pm

dr johnny fever wrote:Yes, but I’d like to try the chebby rockers first. once I get the EFI exhaust manifold, Clifford intake + (whichever) new carb, and the 1.7 rockers I think that’ll give me plenty of pep until it’s time to rebuild the motor. It has 350k in it, so it’ll be there at some point.

The 1985 and 1986 heads do not have rocker studs. You would need to drill and tap for screw in studs and add pushrod guide plates in order to install the Chevy Six or BBC rockers.
https://www.dropbox.com/s/raics8rx0g9rx ... 5.JPG?dl=0
https://www.dropbox.com/s/dlwsfdl82ziie ... 4.JPG?dl=0

Another option is to use the Scorpion 1.73 ratio roller rockers that are pedestal mount and should be a direct bolt on.
https://www.summitracing.com/parts/scc- ... /make/ford

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dr johnny fever
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Re: Single or Dual Clifford Intake?

Post #7 by dr johnny fever » Mon May 21, 2018 8:27 pm

pmuller9 wrote:Another option is to use the Scorpion 1.73 ratio roller rockers that are pedestal mount and should be a direct bolt on.
https://www.summitracing.com/parts/scc- ... /make/ford


After I get the other stuff done I think I might go that route. I know this is sort of a subjective question, but in your opinion how much difference would that make?
1986 F150 4X4

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Re: Single or Dual Clifford Intake?

Post #8 by pmuller9 » Mon May 21, 2018 9:37 pm

dr johnny fever wrote:
pmuller9 wrote:Another option is to use the Scorpion 1.73 ratio roller rockers that are pedestal mount and should be a direct bolt on.
https://www.summitracing.com/parts/scc- ... /make/ford


After I get the other stuff done I think I might go that route. I know this is sort of a subjective question, but in your opinion how much difference would that make?


Here is one test going from the stock 1.6 ratio rocker to the 1.75 ratio chevy rocker on a 240 big six. See post #43
viewtopic.php?p=590642#p590642

The next modification on the same engine. post #58
viewtopic.php?p=593134#p593134

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Re: Single or Dual Clifford Intake?

Post #9 by BigBlue94 » Tue May 22, 2018 10:16 am

I wouldn't go any bigger than a 500 cfm carb. Mine was running a 390 Holley, and now a 450 quickfuel. Both are plenty of carb. I am also running the Clifford intake.
1985 Bronco. 300-6, NP435, 4.56 gears, Detroit locker and tru-trac, 4" lift, and 37" swamper tires. 300 has a 4bbl and headers.

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