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300 triple carb ideas

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Arty808
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300 triple carb ideas

Post #1 by Arty808 » Fri Feb 02, 2018 2:42 pm

Hey all!
I’m looking at running my 300 build (1992 4.9) with 3 Weber 44 IDF carbs (mostly for aesthetic purposes and to say that I successfully made it run). I need some ideas for intakes. I’d like to utilize the stock fuel injected manifold but I don’t know what I may do from there. Any thoughts, prayers, and ideas are welcome!!
1994 Ford F-150 XLT 5.0 4x4
92 Big 300 build

pmuller9
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Re: 300 triple carb ideas

Post #2 by pmuller9 » Fri Feb 02, 2018 5:17 pm

What is the bore spacing on the two throttle plates?

Fordman75
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Re: 300 triple carb ideas

Post #3 by Fordman75 » Sat Feb 03, 2018 12:24 am

A member of this site was working on using the efi lower intake manifold and mounting two Porsche 3 barrel down draft weber carbs on it. He cut the manifold and was modifying the intake. I think using three of the 2V down draft Webers should be do-able. Check the bore spacing on them. Then get some aluminum bar stock to make an adapter for the carbs. The flange on the intake is angled so you may need a thicker piece of aluminum stock. Then angle cut or mill the one side to make the adapter so the carbs sit flat. And if the bores are off a hair you can get them where they need to be with the thicker adapter.

Here's a picture of the one with the Porsche carbs.

Image
Ted

54 Ford F100/F150 4x4
300, NP435 4spd, NP205 transfercase

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Arty808
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Re: 300 triple carb ideas

Post #4 by Arty808 » Sat Feb 03, 2018 6:01 pm

That’s definitely the look I’m going for! I’m not sure on bore spacing, I ordered up of the three carbs so I can mock up the manifold. That’s what I was thinking. Use a length of aluminum stock and create an adapter plate. Another option would be to make a plenum sort of manifold and use rectangular tube stock and tig it all together.
1994 Ford F-150 XLT 5.0 4x4
92 Big 300 build

CNC-Dude
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Re: 300 triple carb ideas

Post #5 by CNC-Dude » Sat Feb 03, 2018 6:32 pm

The bore spacing on numerous 40MM-48MM DCOE's i've CMM'd is 3.550", and the IDF's in that same size range have the same spacing.
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Fordman75
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Re: 300 triple carb ideas

Post #6 by Fordman75 » Sat Feb 03, 2018 10:59 pm

Arty808 wrote:That’s definitely the look I’m going for! I’m not sure on bore spacing, I ordered up of the three carbs so I can mock up the manifold. That’s what I was thinking. Use a length of aluminum stock and create an adapter plate. Another option would be to make a plenum sort of manifold and use rectangular tube stock and tig it all together.


I'm going with 3 Autolite 2100's on my 240 project. It doesn't look as cool as the Weber's. But it's a whole lot cheaper! :D CNC Dude supplied you with the bore spacing info. :thumbup: I don't know how the Weber's will perform on a plenum type intake. All the set ups I've seen them on have been the individual runner with no plenum. The plenums are usually on the air cleaner side of the carb. So I don't know if or how that would effect them. If you go with a plenum, it might be better going three small plenums. And just connect them with some kind of balance tubes. But I think I'd try to just figure out a mounting plate style first.




CNC-Dude wrote:The bore spacing on numerous 40MM-48MM DCOE's i've CMM'd is 3.550", and the IDF's in that same size range have the same spacing.


Thank you for the info!
Ted

54 Ford F100/F150 4x4
300, NP435 4spd, NP205 transfercase

pmuller9
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Re: 300 triple carb ideas

Post #7 by pmuller9 » Sat Feb 03, 2018 11:35 pm

Arty808 wrote:Another option would be to make a plenum sort of manifold and use rectangular tube stock and tig it all together.

Don't do a common plenum.
If the flow of one cylinder is shared by more than one carb, the peak flow in each carb venturi is reduced and it will be as if the engine is over carbureted.

Good example is an intake manifold that has enough plenum volume for a cylinder to draw from to get total fill.
In that case the carb only has to be large enough to supply the average flow of all six cylinders while the plenum volume takes care of peak flows.

In a case where a 44mm carb has about the same size or area as the port, it is best if a single port flows through a single carb without having access to any additional volume. This will to maximize venturi velocity.
Hope this makes sense.

It is also better if the 3 carburetors six butterflies are synchronized rather than using a tube to equalizes runner vacuum.

It looks like there is a .930" difference between the EFI manifold runners and carb spacing.
I would look at cutting the runner elbows off the EFI lower manifold then welding the 3 elbow pairs back on at a small angle towards each other to make up the difference in spacing.
Then weld a new flange across the top of the elbows with the bolt patterns for the Weber 44 IDFs.
Last edited by pmuller9 on Sat Apr 14, 2018 11:39 am, edited 6 times in total.

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Arty808
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Re: 300 triple carb ideas

Post #8 by Arty808 » Sun Feb 04, 2018 5:39 pm

Thanks for the awesome info guys, thank you for the science lesson on the plenum idea, I’m glad I can scrap that! I felt it would also look kind of Mickey Mouse.
Fortunately I have a close friend that is an experienced tig welder so modifying the manifold shouldn’t be to big of a deal.
Once my carb comes in the mail I’ll do up some drawings and ideas and report back!
You all are the best!
1994 Ford F-150 XLT 5.0 4x4
92 Big 300 build

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chad
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Location: Lawrence Swamp, S. Amherst, MA

muli carb use

Post #9 by chad » Thu Mar 08, 2018 12:28 am

just as an asside
there's several threads over on the sm6 forum -
use cycle carbs (both Muckuni & Kehien) as in "1 per cyl."
Several vids on Utube, lota info on use w/4 & 6 cyl motors...

Lastly, if wanting to use an adapter didn't Offy have a 3 1V setup? Doesn't Summit & the others still sell it?
"Big thing is only make one change at a time. Change 2 or more things at a time it becomes difficult to figure which change helped or hurt" turbo2256b » 1/16/2017
Chad - '70 LUEB on '77 frame (i.e. PS, D44, trapezoidal BB 9", 4.11), 250, NV 3550 & DSII to B transplanted, "T" D20/PTO, 2" SL, 1" BL, 4 discs, 33"X15", tool boxes, etc. Seeking: Hydraulic gear motor for Koenig pto. chrlsful@aol.com (413) 259-1749

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