Recommended carburetors for mild upgrade

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Darkbreeze
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Recommended carburetors for mild upgrade

Post #1 by Darkbreeze » Thu Aug 10, 2017 2:25 pm

Just wanting some input. I'm doing a mild cam, Offenhauser single plane intake and EFI manifolds along with .040 over cylinder bore, surface blcok and head and using stock compression pistons. I'm trying to decide on what carburetor to plop down on this and I'm seeing many differing opinions on this with a somewhat general consensus of a 350-390 cfm carburetor, and a lot of people seem to be of the opinion that the Motorcraft 2150 is a decent choice.

However, I came across this article and was wanting some opinions on the validity of this piece as well as any tried and true recommendations regarding fuel delivery options from you guys.

http://www.badasscars.com/index.cfm/pag ... prd440.htm


A 600 cfm 4 barrel (speaking about square bore carbs here) has a 300 cfm primary and a 300 cfm secondary. That means for MOST of your driving needs (under about 1/3rd throttle) you are actually driving around with the equivalent of a 300 cfm 2 barrel, so right out of the get-go a 600 cfm carb is actually SMALLER for normal driving conditions than a 350 cfm 2 barrel. This means the 600 cfm 4 barrel will actually have better throttle response, quicker off the line power and much better low-end get-up and go compared to a 350 cfm 2 barrel. This is compounded even more (to your advantage) when you are talking about a vacuum secondary 600 cfm 4 barrel because no matter what you do, if you mash the gas pedal to the floor, ONLY the 300 cfm primaries will open UNTIL the engine can create enough velocity through it to open the secondaries, unlike a mechanical secondary carb where if you mash the gas to the floor, all 4 barrels will open up and TWO accelerator pumps will squirt fuel into the barrels, thus causing horrible gas mileage if you do that at too low of an RPM. Now obviously if you have a mechanical secondary 600 on your car and you drive with your foot in it pretty much continuously, then that's a bit different other than the fact that any other time, the 4 barrel will out perform the 2 barrel for throttle response and gas mileage.

1964f100240
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Re: Recommended carburetors for mild upgrade

Post #2 by 1964f100240 » Thu Aug 10, 2017 4:23 pm

I really like the holley 1850 vac600cfm works great 300 with a cam and header i have the black spring i think in there now makes the sec open later.

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Re: Recommended carburetors for mild upgrade

Post #3 by Harte3 » Thu Aug 10, 2017 4:52 pm

"I'm seeing many differing opinions on this..."

And that is about the extent of it now and in the foreseeable future. There is no final irrevocable one-size-fits-all answer. With an Offy C manifold you can experiment with 2v and 4v carbs. With the Offy DP you are limited to 4v carbs.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

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THE FRENCHTOWN FLYER
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Re: Recommended carburetors for mild upgrade

Post #4 by THE FRENCHTOWN FLYER » Thu Aug 10, 2017 5:56 pm

His initial premise that "a 350 2V carb is equivalent to a 700 cfm 4V carb is BOGUS. They are not even flow rated at the same intake depression. I stopped reading after that statement - if he can't get that right there is nothing for me to learn here. Actually a 350 carb flows about 250 cfm when rated for a 4V test depression.

I highly recommend the 2150 2V, either in a 1.08 (common on 302 V8s) or the 1.21 (common on 351 - 400 V8s) throttle size.
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Darkbreeze
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Re: Recommended carburetors for mild upgrade

Post #5 by Darkbreeze » Thu Aug 10, 2017 7:45 pm

See, that's why I asked. You can never have TOO MUCH information. 99.9% of mistakes are made because somebody failed to ask ENOUGH questions.

Thanks for the replies, I'm sure I'll have more questions before long.

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Re: Recommended carburetors for mild upgrade

Post #6 by wsa111 » Thu Aug 10, 2017 8:50 pm

1964f100240 wrote:I really like the holley 1850 vac600cfm works great 300 with a cam and header i have the black spring i think in there now makes the sec open later.

Don't be afraid to install a lighter spring to see if your engine will benefit from the earlier opening secondary's
You need to check your A/F ratios from idle, cruising to WOT..
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, duraspark II dist. with MSD-6AL. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
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Re: Recommended carburetors for mild upgrade

Post #7 by F-250 Restorer » Thu Aug 10, 2017 9:09 pm

The Edelbrock 500 cfm, 1403, with electric choke will work fine, as will the Holley the other member mentioned. The Holley 1848, 465 cfm, works well too. Summit Racing also makes, or, I should say that Holley makes it and sells it through Summit, a 500 cfm carburetor that is a copy of the legendary Autolite 4100. It has the annular fuel discharge, which Ford patented in the 50's, and is used today on Fitech injection systems. The carb that Summit sells is the Autolite copy that Holley made, the 4010, I believe was the model number. It has been improved with a Holley choke, Holley center hung floats, Holley jets, acc. pump and acc. cam.

Good luck.

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Re: Recommended carburetors for mild upgrade

Post #8 by Darkbreeze » Thu Aug 10, 2017 9:43 pm

Thanks for those suggestions. I'm going to look into those.

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Re: Recommended carburetors for mild upgrade

Post #9 by Darkbreeze » Fri Aug 11, 2017 3:11 am

Do you have a link for that 4010 on Summit. I'm not seeing it. I'm only seeing parts for them.

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Re: Recommended carburetors for mild upgrade

Post #10 by Darkbreeze » Fri Aug 11, 2017 4:08 am

Kevin, are you still making or are you willing to make, those heat plates? Just wondering. I may make it myself as I've got some good steel plate stock and the necessary tools, but I'm just fairly certain yours look better than mine will. Cutting the thick plate stock is really a pain for my setup as well. If not, cool. Just wondering.


Edit: I see on the ford trucks forum you said you weren't making them anymore. That's too bad. Any voice of experience type advice on making my own? Just figured you've already made all the mistakes and learned from them during the process so I might as well benefit from your experience. Thanks.

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Re: Recommended carburetors for mild upgrade

Post #11 by Darkbreeze » Fri Aug 11, 2017 3:31 pm

So I've located an F2-2150 1.21 351 CFM Motorcraft carburetor, used, needs to be rebuilt but that's no problem, for 25 bucks.

The camshaft I'm planning to use is the Comp cams 66-236-4 with 252 duration, 206 duration@.050 lift, .433 valve lift, .272 lobe lift, 500 to 4500 RPM range, 110° lobe separation and 106° centerline.

To reiterate I'll be using the Offenhauser C series intake manifold, EFI exhaust manifolds, stock style pistons and cylinders bored to .040.

Is this carburetor going to be a good fit or would I in fact be better off looking to a 4 barrel unit? Thanks.

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Re: Recommended carburetors for mild upgrade

Post #12 by THE FRENCHTOWN FLYER » Fri Aug 11, 2017 4:34 pm

You know my feelings, the 2150, but you will need a 2V-to-4V adapter for the Offy intake. No big deal. You could even make one to try out out of hardwood if you are proficient at woodworking. The preferred carb placement would be centered over the plenum, with the carb oriented as in a V8, i.e., with the carb fuel bowl forward.
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Re: Recommended carburetors for mild upgrade

Post #13 by Darkbreeze » Fri Aug 11, 2017 8:44 pm

2150 Purchased. Had to make a 60 mile round trip drive to get it, but for 25 bucks I feel like it was well worth it. Carb is in very good shape from the external appearances and all linkages move smoothly. Like the commercial says, here wego. Thanks to everybody who chimed in.

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Re: Recommended carburetors for mild upgrade

Post #14 by Darkbreeze » Sat Aug 12, 2017 3:40 am

Is there a specific adapter plate or adapter brand you recommend? I'm having a heck of a time finding anything that specifically says it fits the 2150 OR the 6227C manifold. I know both are probably a fairly standard mount spacing but almost all of the adapters I see aside from the really cheap Transdapt and Mr. Gasket models specifically state what carburetors or mounting dimensions they fit or are intended for.

25 years working in and around shops you'd think this would be a piece of cake, but the lack of information, or my inability to form a search string that makes Google happy, is pissing me off. LOL.

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Re: Recommended carburetors for mild upgrade

Post #15 by bubba22349 » Sat Aug 12, 2017 8:28 am

Autolite / Motorcraft 2V and 4V carb's have the same mounting bolt pattern as the Holley carb's. Good luck :nod:
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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.

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Re: Recommended carburetors for mild upgrade

Post #16 by F-250 Restorer » Sun Aug 13, 2017 2:22 am

Darkbreeze wrote:Kevin, are you still making or are you willing to make, those heat plates? Just wondering. I may make it myself as I've got some good steel plate stock and the necessary tools, but I'm just fairly certain yours look better than mine will. Cutting the thick plate stock is really a pain for my setup as well. If not, cool. Just wondering.


Edit: I see on the ford trucks forum you said you weren't making them anymore. That's too bad. Any voice of experience type advice on making my own? Just figured you've already made all the mistakes and learned from them during the process so I might as well benefit from your experience. Thanks.


Carb link: https://www.summitracing.com/parts/sum-m08500vs You know, I don't want to step on anyone's toes here. But I've played with many carbs, and there is a lot to be said for taking a new one out of the box and knowing that no one has drilled orifices larger than oem, that the t.shafts don't leak, that there isn't a piece of copper wire trapped inside an internal air bleed passage, etc.

Hello, 1/4" plate for the base. There's a gasket to use as template. Use 3/8" galvanized elbows welded right to the plate. Use 3/8" pipe nipples. Cut off the end where the hose will attach, and either weld on a hose bib, or weld a bead around the pipe to help hold the hose on. Orient the pipes 45* right and left from the center of the plate, and 9" long. Yes, 9" long. Mine are 7" long and it's a pain to get at the hose clamp. Weld where the pipe tube attaches to the 90* elbow, and where the elbow sits on plate. No leaks ever that way.

There's a guy on ebay, Hollister Road, who makes them. I think he's charging $65, plus shipping. Or google the company. He makes e-fan controls too. His model, however, only has about 4" tubes, so it's a major pain if one starts leaking. He might make them longer if you ask. Oh, a word of caution: Galvanized is bad news to weld as is. If you do it, grind the galv. coating off the weld area first, and use GOOD ventilation. It can seriously hurt you. Of course you can go to a steel yard and buy some scraps and tube, and a couple of 90* steel elbows. Cheers.

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Re: Recommended carburetors for mild upgrade

Post #17 by dan240 » Wed Aug 16, 2017 12:18 am

DarkBreeze- I have the carb you just picked up in my 83 Bronco with basically the same upgrades except I am running the factory cam. I use my truck for hauling our camp trailer and offroading with the family. I've been really happy with it. It runs well and is simple to work on. It won't stumble at steep off camber inclines and starts easily.

I would add a phenolic spacer (thermal spacer) to your parts list. This is probably obvious to most as they came this way from the factory but when I first got the carb it was bolted directly to the intake manifold and I managed to vapor lock the truck. It only did it while idling over rocks for several hours at ~7000' in 90+ degree weather with the AC on but after I added the phenolic spacer I haven't had the same issue.

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Re: Recommended carburetors for mild upgrade

Post #18 by Darkbreeze » Wed Aug 16, 2017 2:58 am

Thanks again for the replies. Unfortunately I don't have another 300 bucks right now to shell out on a brand new carb. Possibly later or if I come across a good deal on a choice 4bbl I might go that route at a later date seeing as I'm seeing a lot of Ford 300 users that are claiming they work well. I see a lot of folks saying the 2150 I just got works well too, so half one dozen of the other.

@dan240, I don't suppose you happen to have a link or part number to an adapter like you're talking about that will bolt this 2150 to the Offenhauser intake? I've been doing a lot of reading on the Mr. Gasket, Specter and other cheap adapters that are supposed to be reversibly univeral for 2 to 4 AND for 4 to 2, and the consensus is that there is nothing but problems with these resulting in a variety of issues such as vacuum leaks through the bolt holes, warped mounting surfaces, linkage interference and power valve interference among other problems. I'd really prefer to retain what hair I have left and also not further damage my one remaining good nerve.

If anybody can provide a link or part number to a recommended adapter that they can verify works to put this Motorcraft 2150 on this Offenhauser 6227C intake, that would be fantastic.

On another note, Kevin, I ran into that thread where it was mentioned that the Offenhauser intake has "Do not use with water plate" stamped on it, and mine has this as well. Can you tell me if the long term consensus is that this is NOT a problem, despite the disclaimer, since clearly it's been a good long while since many of you have been doing this and can probably positively say "it's a non-issue" or "eh, it's usually not, but there's been a few problems here and there." Thanks to all.

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Re: Recommended carburetors for mild upgrade

Post #19 by F-250 Restorer » Wed Aug 16, 2017 12:12 pm

I don't know why Offy began writing that on their intakes. I suspect it is because the newer ones may be made in China, and so there are some quality concerns regarding the porosity of the casting.

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Re: Recommended carburetors for mild upgrade

Post #20 by wallen7 » Wed Aug 16, 2017 2:17 pm

Try this adapter it will center the carb on the manifold. We used these on Nascar LMS series motors with a Holley 2 bbl.
Moroso 64966 - Moroso Carburetor Adapters - Summit racing

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Re: Recommended carburetors for mild upgrade

Post #21 by Darkbreeze » Wed Aug 16, 2017 11:17 pm

@Wallen7, I don't see any way that unit will work because unlike the Holley, the Motorcraft carb has a real interference issue, apparently, with the power valve that sits down by the base. There is no relief in that relatively wide adapter plate to accomodate the power valve. If I'm wrong don't hesitate to point out the error in my observations.

I also went and bought one of those Mr. Gasket 2bbl to 4bbl adapters just to take a look. I'm returning it promptly as it is entirely wrong. It doesn't even orient the carburetor in the correct position and puts the throttle linkage either on the side towards the fender or against the engine because the adapter only lines up with the 4bbl mounting holes on the intake one way. Neither of which is acceptable. Not sure how they even sell these PofS really.

I'm beginning to think I'm going to have to fabricate an adapter plate myself, but I'm baffled how all these people are supposedly using these carburetors on these intakes, and nobody sells an adapter that's designed to accomodate this configuration, universally or specifically.

I'm also starting to think maybe I should have just found a smaller four barrel and went with that. I might end up just having to eat that 25 bucks for now and doing that anyway. I dunno. Been an exciting process so far, but this particular aspect of the build is seriously sapping my enthusiasm and creating some unexpected frustration.

As a matter of fact, now that I'm investigating a bit more thoroughly, I can't find a single image or instance of anybody with the usage of the 2100 or 2150 on the Offenhauser 6227 or 6227c intakes. Seems spectacularly unusual that there are no images at all online of anybody using this combination, but tons of images of people using four barrels on them. Obviously that doesn't mean it hasn't been done, successfully even, but it's telling that I can't find them to even look at how they have things configured by getting a visual picture.

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