buick 225 v6 carb

I have a 1971 cj5 with a Buick 225 v6. The carb is a rochester 2g, the id on the side of the carb designates it as a v8 model. Does anybody know if this is the stock carb if so what is the original jet size?
Thank you

 

Seems like you have the wrong carburetor.
Correct Rochester 2 GC numbers for Dauntless 225 are not the same as for other GM applications.
What number 2GC you currently running ?
Was your 1971 originally equipped with an air pump ?

 

The number on the carb should read 7041185

 

If you have the carb. no. I might be able to give the part no.'s.And app's.

 

I robbed a 2g off an early 60's Chevrolet v8 from the junkyard, and after rebuilding it i'm getting 16mpg city out of it in my 62 CJ5 with stock drivetrain. Seems to work okay to me, if all you can find is one off a v8, run it!

 

Original jets for the 7041185-137-1-1 were:
Sea level to 5000ft. .051
5000ft. to 10,000 .049
Over 10,000ft. .047

 

The number is 7029140 and yes it did run an air pump. Reason for post only getting 11 mpg

 

7029140 belongs to a 1969 Buick 350.
Using a carburetor thats internally calibrated for a larger discplacement engine can cause the smaller displacement engine to run excessively lean. As in burnt valves !

 

Fwiw,
I did some digging in my book, 7029140 is a 2GV, the 2GV is a auto choke model. However, a vac. break diaphragm unit(s) is used in place of the conventional choke HSG and choke piston. The thermostatic coil is located on the intake manifold and is connected to the choke valve by a linkage. The only 2GV listing in my book for a jeep is a 1968 Kaiser jeep 350 V8. Date of pub. Nov. 1971. I have the settings for that carb.#, but not the jet # 's.Sorry.

 

:iagree:

How is a carburetor calibrated for a larger displacement engine which will require MORE fuel going to cause the engine to run lean?
I'm interested in learning more...

 

Anybody know where I can buy a Rochester 2g #7041185 ?

 

dd

 

I base this statement on a couple of conversations I had with Jon Hargrove , proprietor of The Carburetor Shop.

 

An automotive carburetor is a device in which fuel is combined with air to provide an explosive mixture.
This mixture can be lean, neutral or rich.
The rich mixture is proportionately high in hydrocarbons while the lean mixture is proportionately high in oxygen levels.
Higher oxygen levels produce higher burn temperatures which potentially can burn the valves.
More air = more oxygen = increased combustion temperature = valve burn.

The internal combustion engine is basically a vacuum / pump.
Crankshaft revolution is derived from gaseous pressure either lesser or greater than atmospheric pressure.
Vacuum pulls in the charge while charge combustion pressurizes the chamber.
As engine displacement goes up so does the charge volume which is rated as CFM.
CFM need raises proportional to engine displacement and the crankshaft velocity.
The charge mixture is effected by heat and air velocity.
Since the temperature remains relatively constant the main way to effect the mixture is via air velocity.

In order to increase the CFM, a carburetor designed for a larger engine will utilize a larger throttle bore.
When increasing the throttle bore diameter it should be fairly obvious that the air volume will be increased.
This larger throttle bore allows a greater volume of air to pass.
The venturi size is also increased to handle the greater CFM.
When a carburetor having an over sized throttle bore / venturi is used,
the air velocity decreases because the CFM requirement decreases for an engine with less displacement.
When air velocity decreases, the air / gasoline mixture becomes effected.
Decreasing the air velocity fails to properly atomize the gasoline.
Within the carburetor there are several circuits .
Except for the accelerator pump circuit more gasoline needed to enrich the mixture is available only via vacuum.
Vacuum at the venturi is reduced if the air velocity is decreased.
This results in a lean mixture because the amount of air to gasoline is increased.

 

I know this post is from 7 years ago but what did you do with the 2g V8 carb?

 

The OP hasn't been on here since 2012, so I doubt you'll get a response.
If you need a carb, best to post a "want to buy" in the classified section.

 

That lean comment makes sense after @oldtime explained it. Burned exhaust valves are a real concern even on modern cars. My 2004 Subaru burned an exhaust valve, thankfully it took 200000 miles to do it and I had virtually no other problems with the car till that point.

 

After read this thread, checked my Carb. # 7036146. Should I use it or start looking?