4 bolt and 2gc

[47 flatbed]

Looking for the prep work needed to make this work. Intake is cast.(hersery find 2 years ago) 2gc with electric choke. Is there any plugs or areas that need to be adressed with the intake. I also left a message at Bubba's for an igintion. Thanks in advance.
Mike

[47 flatbed]

Engine is 4" merc crank, bore is 60 over and mild isky cam.

[47 flatbed]

8ba

[GreenMonster48]

I have this set up, but I haven't tried it out yet. The fellow that sold it to me said the following "When I used a Rochester carb on an old Merc intake, I first used a Merc
> gasket then a metal plate (that matched the bottom of the Rochester carb)
> and then a Rochester carb mounting gasket."

Thought that might be helpful. I think there is a small hole in the side of the intake for a choke tube or something. That would probably need to be plugged.

[tubman]

Here's what you need to know. The small base 2GC came early on GM V-8's and some V-6's ('50's - 60's). As I said before, the small base carbs bolt right on to the Merc manifolds (as GreenMonster48 said, there are some open passages in the bottom of some 2GC"s that may require an adapter/block-off plate). If you mount the carb backwards from it's usual orientation, the throttle linkage and fuel lines drop almost exactly into place. Unfortunately, this puts the manual choke linkage on the wrong side of the carb with a backwards pull. I have an aluminum later model Canadian Merc manifold with provisions for an automatic choke. On this set up, the choke tube is on the proper side of the manifold, and the choke tube mated to the 2GC with a minor bending.

As to a cast iron manifold; it should work as well as a Canadian aluminum on if prepped properly. I used an aluminum manifold because I figured it would be easier to bore. I purchased an arbor and a 1 7/16" cutter from an outfit called "Rotobroach" (or perhaps Rotabroach - hyphens optional). The bad news is that the cutter and arbor cost almost $100. The good news is that it worked so well on the aluminum, that I think it would work well on cast iron. I did mine with the manifold clamped on my benchtop drill press and had no problems at all. I used a spare 2GC base as a guide to keep the cutter centered. This method has the advantage of putting the bores in the manifold exactly the same as the carb.

[Binx]

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I'm still in the setup phase too. As GreenMonster said it will need an adapter plate to support the back of the carb which overhangs the manifold. The carb will seal without it but there isn't good surface bearing to tighten the nuts. the two 1/8" holes where the old choke actuator sat will need to be plugged. I'm pretty sure the bigger crossover tube can be left open on pass side. I don't think it is open to exhaust gasses.

Lonnie

[alan]

I run an 8ba in my 41 truck with a 2GC carb from a V6 buick engine used in a 66 Jeep, 4 bolt Merc intake, carb mounted back ward, adapterted to throttle/choke, used the dash throttle hole for the chock rod, did not need throttle rod, seems to work in SC with no problems. I also used a 2GC off a 307 chev, changed out jets to make it work, used as my spare now.

[Binx]

Nice work alan!! The 8CM manifold is much neater.

Lonnie

[Binx]

Mike, make sure the holes in the throttle base near the front mount holes are plugged as well as the vacuum signal port on the back under fuel inlet

Lonnie

[scooder]

What sort jetting are you lot using in the 2g on a flathead? How do they compare to a 94 or 885 Economy and power. On the original 8CM the choke pulled exhaust warmed air through the exhaust heat riser. What did the 2g use for its choke? Was it exhaust warmed air, or actual exhaust gas? I ask incase someone wanted to run the stock 2g choke?
Many thanks.
Martin.

[Ol' Ron]

Using the 2GC on a merc or Ford intake the throttle bores are smaller. Using a die grinder you can blend in the interference areas. However to take advantage of the increasec AF flow of the 3G it best to bore the intake to match the carb, or why use it in the first place. The open bace of the 2GC can be willed with JB weld and the center hole drilled for the ford mounting can be drilled through the Vacuum port for the carb, thus mounting it on a ford intake. Using an AF meter is the best way to tune it, especially if running a hot cam. you may have to cut some coils from the PV spring. This is a great carb and provides excellent power and economy when tuned properly. Remember it needs the SBC dist to run right

[47 flatbed]

My intake mounting looks a bit more solid than described?

[47 flatbed]

pictures help

[47 flatbed]

Intake

[47 flatbed]

Try right side up

[scooder]

Hello Ron,
I'm fiddling here with an 8CM manifold and carb (885) and a Rochester 2g. Both these carbs here have the same throttle bores, both are also bigger than the holes in the manifold. Makes me wonder if the 885 with the opened manifold might be another good choice.
Do you know what the 2g used in it choke heat, warmed air or actual exhaust?
Thanks,
Martin.

[Binx]

scooder, here's a site that may help answer the choke questions

http://oldcarmanualproject.com/manua...nual/index.htm

Lonnie

[47 flatbed]

Basically there is little to be done besides a plate between intake and carb?

[oldbugger]

I am using the 2g on my 53 merc engine with good results. I solved the choke issue with electric choke setup, 12v, works great. easy to hook up pcv valve also. need the gm dist. good luck

[scooder]

Originally Posted by 47 flatbed

Basically there is little to be done besides a plate between intake and carb?

Seems that way, use the plate for carb support, mount the carb arse about face to make the throttle linkage easyer. Sort out choke, which ever way you fancy. Seems stock jetting is good to go, or at the least a good starting point to tune properly.
All good info thanks all.
Martin.

[Ol' Ron]

I don't really know anything about the 885 carb. Ford had a large bore 94 style carb on late PU's. I used them on the Hydro engine. Ran well, used allot of fuel.

[47 flatbed]

Chevy conversion from bubba has been ordered. Now for some truck water pumps and we should have an engine to fire up soon

[47 flatbed]

Couple steps closer. Installed pcv valve mock up carb and alternator for belt lenght. Thanks to Bubba for prompt service

[Zeke...PA]

Here is a photo of mine going together. Zeke

[HCO41]

I'm going to use the Rochester 2gc on my stock 8ba along with one of Charlies' GM distributors. I've had the Merc. manifold machined to match the 2gc base and am proceeding with the carb. rebuild. I have a couple of questions:

1. I've bead blasted the carb. base. What's a good, gas resistant, paint I
can use to protect it?

2. What's a good place to start with the power valve and jet sizes for this
application? (Jets are #55 as is).

Thanks,
Howard

[Binx]

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Originally Posted by HCO41

2. What's a good place to start with the power valve and jet sizes for this
application? (Jets are #55 as is).

Thanks,
Howard

That is an excellent question that I am also wondering.

Lonnie

[Ol' Ron]

Thia is where an AF meter comes in handy, Plug reading doesn't work well with the new gas.

[Ross F-1]

On Ron's excellent advice, and my paranoia about possibly running too lean, I bought an AFM and used it to tune my Rochester. My 2G was for a '63 283 and was supposed to come with #55's, but when I opened it I found #54's. It was showing to be consistently fat so I stepped down to #53's and it runs great. Air/Fuel ratios at cruise are in the low 15's for the most part. What surprised me was how sensitive cruise AFR was to the idle mixture screws. Best idle position for the screws made cruise ratios fat; 1/8 turn in and AFR's jumped up a full point.

On a side note; I could see clearly on the AFM that the PCV system really messes with the 2G calibration. The idle screws need to be out enough to compensate for the PCV flow, which as I noted affects cruise AFR. I ran with the draft tube re-installed, and everything was much more consistent. I can only assume that later model carbs are calibrated to deal with PCV.

[Alaska Jim]

Ross, what type of A/F meter did you buy approx. cost and where? sounds like some thing I will need in the future.---Thanks .--Jim

[Ross F-1]

I bought the one Richard in Florida recommended; the Innovate 3844 MTX-L, about $150 on eBay.
http://www.ebay.com/itm/Innovate-384...item2c7c7dd4ee

It worked flawlessly and has good software. Here's a sample of the output (with notes)

[alan]

I have a 8cm engine, Isky 77b cam, 2GC off a 66 buick v6, run 53 jets, tried 49, 51, 54 and like the 53's best

[Ol' Ron]

The Power valve in the 2GC can be tamed down by removing a coil or two fron the return spring

[47 flatbed]

Awesome notes on tune. Need to finish assembly of block components and we'll run her.

[Alaska Jim]

Ross, I take it that the A/F meter only has one oxy. sensor and is used in only one bank, and single exh., and that you would need 2 for true dual exh.? sorry it took so long to get back to this post. any info is appreciated.---Jim

[av8coupe]

Will a stock fuel pump supply enough pressure for use with the 2G?

[Ross F-1]

Originally Posted by Alaska Jim

Ross, I take it that the A/F meter only has one oxy. sensor and is used in only one bank, and single exh., and that you would need 2 for true dual exh.? sorry it took so long to get back to this post. any info is appreciated.---Jim

I have headers and true duals, put the sensor in the PS. This thread is full of good info on AFR's: https://www.fordbarn.com/forum/showthread.php?t=121983

[itsa52]

Someone asked about paint,,,http://search.eastwood.com/search?w=carburator I haven't used it but have faith in Eastwood.

[Henry/Kokomo]

In answer to av8coupe - the stock fuel pump seems to work fine on my 276" 8ba engine with Rochester 2GC.

[HCO41]

There are several excellent carburetor builders on the forum that do the stock Ford carburetors. Is there anyone out there providing the same service on the 2GC for flathead use?
Howard

P.S. Should this be addressed to the H.A.M.B.?

[Ross F-1]

In searching for tuning info and jets for mine, I found there is at least equal support for the Rochesters. I got my first 2G off a Craigslist ad, but not knowing anything about them, I got screwed. There are several maladies to watch for. So I bought a professionally rebuilt 2G off eBay with warranty, and it has been trouble-free. It was about $180, less than a brand new 94.

PS, there are a jillion calibrations and variations on 2G/2GC's, go ONLY by the part number cast into the bowl cover or on a tag. You can look them up on-line, you want one from a small engine (< 300 c.i.).

[shoe box Jack]

HI Ron. I have a rebuild 55 ford carb. with 56 jets. Will this work on the 255 flat head? Thanks for any info. Shoe.

[scooder]

Ross, what are the maladies that need looking for? Could help a chap on the lookout for a carb.
Many thanks,
Martin.

[Ol' Ron]

used those caebs on the Hydro 284 engine and I think the jets were 52 when we ran it in the dyno. bbut that might have been a little fat. try and hook up an AF meter for cruising around, dont need a rich engine on the street.

[Ross F-1]

Originally Posted by scooder

Ross, what are the maladies that need looking for? Could help a chap on the lookout for a carb.
Many thanks,
Martin.

An easy thing to look for is that the air cleaner bridge across the choke isn't broken out (gone or cracked). Holley 94's air cleaners just clamp onto the OD of the air horn; on 2G's there is a stud or bolt that holds the air cleaner down. Over-tightening the air cleaner can break this bridge clean out of the air horn. There are repair kits for this but I'd avoid carbs that are busted.

[HCO41]

I was given two of these 2GCs, with the hope of getting one good one out of them. Both had the same PN in the casting, yet there were differences. One didn't have a venturi vacuum port but did have a "Y" vacuum fitting in the base, one approx. 1/4", the other larger. I'll be using a SBC distributor and wondered if the smaller port in the "Y" should be used for the vacuum advance source? There seems to be several criteria that make for a good application:
1. Small G2C base
2. Venturi vacuum source
3. Choke dashpot in top (my preference)
4. Fuel input on left side (after 180* turn), (same side as dashpot)
Is there any other considerations for this application? Also, does anyone know a source that shows the different applications where these carbs. were originally used?
Thanks, Howard

[Binx]

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check these out...

http://www.carburetorexchange.com/do...arburetors.php



Click on the kits to see casting numbers and applicability at this site

http://carbkitsource.com/carbs/tech/...Jet-index.html


Lonnie

[Ross F-1]

Howard, why use venturi vacuum? No advantage.

[Ol' Ron]

Howard, When using the SBC dist the vacuum should be taken from the intake manifold.

[scooder]

Thanks Ross.
Martin.