2 x 4 Carbs.

[Joe Fisher]

I am putting a 2 x 4 setup on my 61. I am rebuilding the carburetors. Can anyone give me a way of telling if it is a 245HP or a 270HP? Can you tell by jets and metering rod size?
Top # 6-1299, main # 0-1049, throttle # 1-1387. The front carb. has no provision for a choke.
Thanks,
Joe

[Jack H.]

Re: 2 x 4 Carbs.

All is described very nicely in the current Judging Guide. The '61 dual 4-Bbl setup differed from prior years to accommodate California emissions. The forward carb changed from 2626S to 3181S for 245 HP with the difference being the presense of a drilled/tapped hole on rear of the throttle plate. For 49-State shipments the rear hole was plugged. For Cal emissions cars, this was used as an attachment point for the PCV valve.

Difference(s) between 245 HP and 270 HP dual 4-Bbl carbs is several fold dealing with the size/length of counterweights, the orientation (up vs. down) of the main nozzle on the primary side, and the Carter tags/ID. Get the book(s)....

[Jack H.]

Re: 2 x 4 Carbs.

All is described very nicely in the current Judging Guide. The '61 dual 4-Bbl setup differed from prior years to accommodate California emissions. The forward carb changed from 2626S to 3181S for 245 HP with the difference being the presense of a drilled/tapped hole on rear of the throttle plate. For 49-State shipments the rear hole was plugged. For Cal emissions cars, this was used as an attachment point for the PCV valve.

Difference(s) between 245 HP and 270 HP dual 4-Bbl carbs is several fold dealing with the size/length of counterweights, the orientation (up vs. down) of the main nozzle on the primary side, and the Carter tags/ID. Get the book(s)....

[Joe Fisher]

Re: 2 x 4 Carbs.

Jack, what books? I have Nolan Adams, the AIM, the 61 Manual, the ST-12, NCRS number book and the parts book.
The information I am looking for is not in these books. I would like to know what the internal differences are, refering to jet size and metering rods. I am using an hydraulic cam, and I been made to undstand the jetting is larger on the 270HP, but would like to know for sure.
There are no tags on the carbs, if there were I wouldn't ask.

[Joe Fisher]

Re: 2 x 4 Carbs.

Jack, what books? I have Nolan Adams, the AIM, the 61 Manual, the ST-12, NCRS number book and the parts book.
The information I am looking for is not in these books. I would like to know what the internal differences are, refering to jet size and metering rods. I am using an hydraulic cam, and I been made to undstand the jetting is larger on the 270HP, but would like to know for sure.
There are no tags on the carbs, if there were I wouldn't ask.

[Clem Z.]

Re: 2 x 4 Carbs.

the 3181 and the 2627 were 245 hp,and 3182 and 2614 were the 270 hp carbs. i will scan you a copy of the internal parts.

[Clem Z.]

Re: 2 x 4 Carbs.

the 3181 and the 2627 were 245 hp,and 3182 and 2614 were the 270 hp carbs. i will scan you a copy of the internal parts.

[Peter Cipriani]

Re: 2 x 4 Carbs.

Joe,
Give Bob Kuntz a call. He advertises in the driveline under services available. He helped me when I restored my 2x4 carbs for my 61. Great guy!! Also, Craig Woodruff carbking@aol.com another good carb. guy

[Peter Cipriani]

Re: 2 x 4 Carbs.

Joe,
Give Bob Kuntz a call. He advertises in the driveline under services available. He helped me when I restored my 2x4 carbs for my 61. Great guy!! Also, Craig Woodruff carbking@aol.com another good carb. guy

[John H.]

Re: 2 x 4 Carbs.

Joe -

I posted this for you over on the CF Board - you'll find the jet/rod specs shown in the back of the "ST-12" on the "Engine-Fuel" specs page, carb usage is from the NCRS Corvette Specs Guide (I don't have a '61 TM&JG, which describes all the external physical differences, weights, etc.):

'61 245's took a 2626S (1st design) or 3181S (second design) front carb, and a 2627S rear carb; 270's took a 2613S (first design) or 3182S (second design) front carb, and a 2614S rear carb.

2626S, 2627S and 3181S all had .093" primary and .053" secondary main jets and .077"x .071" x .068" metering rods, and a #68 (.031") idle jet.

2613S, 3182S and 2614S all had .106" primary and .061" secondary main jets and .071" x .050" metering rods, and a #65 (.035") idle jet.

[John H.]

Re: 2 x 4 Carbs.

Joe -

I posted this for you over on the CF Board - you'll find the jet/rod specs shown in the back of the "ST-12" on the "Engine-Fuel" specs page, carb usage is from the NCRS Corvette Specs Guide (I don't have a '61 TM&JG, which describes all the external physical differences, weights, etc.):

'61 245's took a 2626S (1st design) or 3181S (second design) front carb, and a 2627S rear carb; 270's took a 2613S (first design) or 3182S (second design) front carb, and a 2614S rear carb.

2626S, 2627S and 3181S all had .093" primary and .053" secondary main jets and .077"x .071" x .068" metering rods, and a #68 (.031") idle jet.

2613S, 3182S and 2614S all had .106" primary and .061" secondary main jets and .071" x .050" metering rods, and a #65 (.035") idle jet.

[Steve D.]

Re: 2 x 4 Carbs.

Clem

Why was a 2x4 setup never offered on the 327? Could a 2x4 setup on a 327/300 accomplish anything for low and mid range street RPM ?

Steve

[Steve D.]

Re: 2 x 4 Carbs.

Clem

Why was a 2x4 setup never offered on the 327? Could a 2x4 setup on a 327/300 accomplish anything for low and mid range street RPM ?

Steve

[Clem Z.]

Re: 2 x 4 Carbs.

i have no idea except they went to the AFB carb in 62 which would not cut out in sharp turns while racing or autocrossing like the WCFBs would. "been there done that" the fuel distribution while crusing on just the rear carb on the 2X4 setup is very poor and i think a good single carb is better unless you are after just "the look".

[Clem Z.]

Re: 2 x 4 Carbs.

i have no idea except they went to the AFB carb in 62 which would not cut out in sharp turns while racing or autocrossing like the WCFBs would. "been there done that" the fuel distribution while crusing on just the rear carb on the 2X4 setup is very poor and i think a good single carb is better unless you are after just "the look".