225 V-6 Carb Help

I am having trouble identifying the proper carb for an intake manifold I have. Problem is the small base 2GC is too large, bolt pattern wise (Bolt/stud spread on manifold is 1 7/8 x 3 1/4") for my manifold. Manifold casting # is 1378704-E, which is the spec manifold for the Dauntless engine and should accept a small base 2GC, however, on mine the bolt pattern is too small to fit a 2GC. I even found a 2-Jet, as well as a 2G, both of which are too large (bolt pattern wise). Intake bore dimension is 1 7/16" on 1 5/8" centers. I'v been all over the I-net looking without success. The engine is in my M38 and I'm not sure of the year. Engine has a single barrel and I'd like to convert it to the 2 bbl. in order to accommodate a better carb, not to gain HP or torque. I'd also like to know what the original application was for this manifold. I may need to find a different intake that will accept a 2GC.
Thanks for the help! Waldo

 

The single barrel Rochester used on early 60s Buick V6 is considered by many to be the worst carburetor ever designed. Not sure how you determined a manifold for a that carburetor was "Spec" for a Dauntless, but that combination was never used on the Jeep application of the V6.

Your best bet is to find a two barrel manifold and carburetor that fits your engine.

 

There's 2 different sizes of Rochester 2G/2GC carbs. The bolt patterns are about 1 bolt hole different. Easy way to tell, the small version has a 2 5/16" air cleaner mounting base, the large version is 3 1/8".

 

The dimensions for the large bore and small bore 2G carbs are noted in this post: Replacement Rochester 2g Carb

You can use that to figure out what your carbs and manifold are. That manifold should be a standard small bore 2G setup. It sounds like you've been finding large bore carbs.

Another thing to note: If the V6 currently has a one barrel carb, it may be a 198. That was the original V6 before the 225. They are largely similar but the 198 has a different bellhousing. It also has a lower deck height so the 225 manifold won't fit. The 198 is harder to get parts for since it was only made a few years 60+ years ago and isn't super desirable.

 

I posted a reply here last week, but it seems to have vanished. Thank you for the reply Mr. Fireball. I was wondering if you could elaborate on the bell housing details so's I can determine if I indeed have a 198 and not a 225.

 

A 225 will have the standard Buick, Olds, Pontiac bellhousing (BOP) with two high top bolts and a dip between them like this:


A 198 will have the Buick 215/Rover V8 bellhousing that is mostly round with a pair of odd ears just outside the top two bolts:

 

The mud finally dried up enough to get to the jeep. Turns out I have a 225, as per bellhousing at the top. Yeaa! I'm guessing the engine is from a car, thus the 1 bbl. carb. This probability likely means I don't have the heavy flywheel, something I would like to have. Figuring this out will require the VIN number to determine the donor vehicle. After scouring the I-net, I determined the engine #'s could be almost anywhere. There were no numbers stamped on the drivers side block face, where most resources said it would be. There was however, a stamped number on the front face of the head. I'v never seen such a thing. The # is ER21972. I'm hoping to find the engine # under the alternator, on the passenger side block face. I can't see the build code either as the exhaust manifold gasket obscures the deck ledge.
Thanks for your help Fireball, Waldo

 

I have a single barrel carburetor and manifold taken off a Buick 225. Those old Rochesters are not the best carburetors, and many consider them the worst one ever designed, but that engine ran okay for many years. It sat for many years, so I am sure the carburetor would need a cleaning and kit.

If you want it all it will cost is postage.

 

Pappy, Thank you for the offer, but the single bbl is what I'm hoping to get rid of. I have a 2 bbl intake I intend to exchange for the current 1 bbl POS. At this point, it's the carb I'm needing. Any rebuildable SMALL BASE Rochester 2 bbl. from the "2 Jet" series would work (2 Jet, 2C, 2G, 2GC, 2 GV).
Chuck, I'm assuming you mean a casting number. I'll look today. This brings up another advantage of owning an M38.... the trans cover is more like a removable floorboard, giving ready access to that area (something I didn't know prior to owing an M38). Very useful access point.
Waldo

 

Lots of 2 jets on eBay, though without paying 375-600 you aren’t getting one set up exactly like a jeep. If looks matter then finding one with the correct fuel inlet is less common.

If you find a small base with auto or hot air choke you can use a Dorman cable kit. That’s what I did, though my carb is still a little sketchy. Probly needs rebushed.

 

Yep, not cheap but here's an original Jeep configuration rebullt carb on ebay for $345: https://www.ebay.com/itm/350747674438

Posting a Want To Buy in the forum classifieds may also scare one up.

 

Note for buying the 2G Rochester carbs off eBay.

You will have to go thru the carb! ie.rebuild it!
You don't know the jet size! They can come with 53's and 56's!
Small parts missing! The steel ball and springs!
No "T" stake!
No manual choke bracket
Throttle linkage is missing the relocation ball stud bracket

I found out the expensive way!

 

Thanks for heads up!
It seems like the part shortage is always the case. I wonder about flange gasket and the air cleaner gasket also.
That place will give you $35 for a core...wow...big deal.
After considering this new carb, I will NOT be purchasing based on the hassle-factor.
I have a reman electric choke carb on the shelf for my 'spare'.

 

I ended up using the original 2G carb that my Jeep came with, doing a complete rebuild. I still have the eBay carb. It could be used, but would have to get another rebuild kit first.

 

Yep - similar story here...I have an electric choke reman carb from Summit and an overhaul kit if needed.

 

Same here I purchased the same one and and it worked for about a year and a half or about 800 miles. Where the throttle brackets mounts to work the butterfly’s on the carb it was pressed on and worked itself off , it is a parts carb now. I did have it tig welded back on until I found a good replacement.

 

So, after scouring the local scrap guy and the only junker in town, I have viewed probably 50 Rochester 2-- (fill in the blank) carbs. They were all "large base", confirmed by the size matched gasket I bought that fits my 2 bbl. (#1378704-E casting) manifold. Am I chasing the wrong carb? Or are they as rare as Aliens? My bolt spacing is 1 7/8" x 3 1/4". Can one of you guys with the same intake casting # measure your carb bolt spacing, please. I may have some sort of oddball intake and I'd really like to ditch the 1bbl. (rebuilt, per the sticker, but runs like they forgot to install the main jet).
Thanks in advance for the help!!
Engine casting # coming soon, lots of gree-gree in there.

 

Got to the engine block casting #'s today and they are B1358435. Which equates to a 1967-74 V6 odd-fire by Kaiser Jeep Corp, AMC (Per Joel's compilation here). This all makes me wonder why it is equipped with the one bbl. carb, as that seems like a backslide to me. The good news is I probably have the HEAVY flywheel as found in Jeeps, and not some other GM car flywheel. Still flummoxed by the carb base, however.

 

As per the thread I noted above, your manifold is a for standard small base 2G: Replacement Rochester 2g Carb

Small base 2GC:


You're probably not finding many in wrecking yards because they only seem to have been used on small(er) engines in the '60s and they standardized on the large base carb for all engines that used a 2G in the 70's.

As I noted above, they can be found on ebay for a price. I have never ordered on of those so I don't know the quality. Your best best is to post a WTB add in the forum classifieds. It's not unlikely someone has a carb they would part with.

I have no idea what all engines used the small base 2G, but looking at the applications for the rebuild kit on Mike Carburetor parts, it looks like a 69-70 Chevy with a 307 would be another source: https://www.carburetor-parts.com/2g-2gv-carburetor-kit-k4262. I'm sure there are others, but they probably have a different choke style and don't use the same rebuild kit.