Author Topic: FE Edelbrock F68 Intake 6X2 intake.  (Read 1001 times)

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FERoadster

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FE Edelbrock F68 Intake 6X2 intake.
« on: May 01, 2022, 09:08:43 PM »
Jay and others: I'm assembling a 6X2 intake for a "somewhat street able" Fe in a lighter car.
I'm wondering if progressive linkage will work. The outermost cylinders may be starved for fuel at lower RPM's.
Plan is to use 2 sets of 3X2 linkage (one for each bank) and adjust so the secondary carbs come in at a lower throttle level.
In Jay's intake comparo book he used WOT as a function of Torque and HP but that would negate any fuel starvation to the outmost cylinders at low RPM's.
Anyone have any experience with the 6X2 intake?
I'm using Stromberg WW's that flow about 30% more than those in Jay's test. I've got about 20 WW's and at least 10 NOS ones.
Any advice?
Richard >>> FERoadster

« Last Edit: May 02, 2022, 09:44:44 AM by FERoadster »

1968galaxie

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #1 on: May 02, 2022, 03:06:59 PM »
No advice - but will look very cool indeed!

jayb

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #2 on: May 03, 2022, 08:41:07 AM »
I agree that with just the center two carbs running, the outside cylinders will be running leaner than is optimal.  That manifold is basically an open plenum under those carbs, and I don't see how the center two carbs can effectively feed the outside cylinders at low speeds.  Nevertheless, I wouldn't let that stop you.  I had no problem getting that manifold to idle on the dyno, so the idle circuits of the outside carbs will still be working, and at low engine speeds I'm sure you could jet the center carbs to make the car drivable.  The inboard cylinders will probably be running rich, and the outboard cylinders lean, but so what?  You're not trying to get a perfectly tuned setup with that intake.  Go for it.  Post pictures!
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

TomP

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #3 on: May 06, 2022, 11:38:13 AM »
I have seen them on running cars with only two carbs actually working, the four corners just being dummies for looks. Can't be any worse fuel distribution than a straight six.

FERoadster

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Re: FE Edelbrock F68 6X2 intake.
« Reply #4 on: May 17, 2022, 11:16:40 AM »
OK it's been a few weeks but i finally got to the intake. What I thought was a match of the Stromberg WW 4 bolt mounting to 2 of the 3 bolt bases was not what I thought.
The 4 bolt bases are just a bit farther apart so I had to drill 2 of the holes from 3/8 to 13/32. I drilled 2 holes of the spacers and the carb bases. The rear 2 holes will have to be drilled and tapped to 5/16. Next issue was the throttle arms for the linkage hit the VC on one bank of the carbs so I rotated one bank so all the throttle linkage is on the inside. I'll just fab a bell crank that has both a push and pull config.
Finally the Stromberg WW's have a much larger size of throttle blades and they hit the intake, the 1" spacers take care of that and I can blend in the mis-match by grinding a bit of the intake. There is a lot of aluminum there so I won't find a problem.
A picture of the mis-match and the intake.
Richard
« Last Edit: May 17, 2022, 11:41:40 AM by FERoadster »

1968galaxie

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #5 on: May 17, 2022, 12:27:25 PM »
Looking good!

Hemi Joel

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #6 on: May 23, 2022, 05:48:18 PM »
Looks awesome, I love those multiple carb set ups!

Now I need to warn you all about a problem you might have. The 8 carb intake that I have on my Hemi was originally on a boat. It has the 3 bolt carb mounting pads, and because the engine is placed in a V drive boat backwards, the carbs were backwards. This caused major bog when I launched at the dragstrip because the fuel would slosh away from the main jets. The solution for me was to remove the carbs, re-drill the mounting pattern, and reinstall the carbs facing the right way.

You might have the same problem, but only on one side of the motor. If that was mine I would figure out how to turn those 3 carbs around and make the linkage work. You might want to switch the throttle arm's on the carburetors so that they point up instead of down. Then when they clear the valve cover?

I run the 4 center carbs as primaries, and the outer 4 as secondary's. I have no idea if the outer cylinders are leaner or not while I am going down the highway at cruise. But it does pull down 15 miles per gallon on the highway and is still capable of going 137 in the quarter mile.
I was advised not to use power valves, that they just mess up the tune when you have this many carbs. So I'm not running power valves at all.
Not sure if you have a linkage set up yet or not. But I use 5/16 x .030 wall stainless tubing with 10 – 32 stainless threaded rod inserted through it, and a spherical rod end threaded on each end. And then jam nuts on the threaded rod to secure each end of the tube tight, and to lock the position of the spherical rod ends in place once it is adjusted. It works out pretty good, I think. I have had some problems with the arm on the cross shaft slipping, where it has to pull 4 carbs open. So I'm working on an improved arm with more surface to grip on the cross shaft.

I love what you're doing, good luck with it.

FERoadster

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #7 on: May 23, 2022, 07:58:53 PM »
Joel Thanks. This will be on a seldom driven only street car so I'm not to worried about overall performance only street ability.
And of course wow factor in a 60 Corvette.
Richard

TomP

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #8 on: May 24, 2022, 05:00:46 PM »
Cool setup Joel!

1968galaxie

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Re: FE Edelbrock F68 Intake 6X2 intake.
« Reply #9 on: May 30, 2022, 11:24:55 AM »