71 140 Rochester 2 bbl JET question

[71GTKammback]

Hey Ya'll,

I have been working on "tuning" my 71 Vega GT Kammback for 18 months now. Recent additions are and Offenhauser 2bbl manifold and a period header for the 140 with a Camaro style muffler with dual exhaust at the back. I added a 72 ram-air pipe to the front of the car to the carb for cooler air. It runs so much better than stock. It is the original stock 140 internally with 50k original miles. I have also added power steering and power brakes.

My question is.....

The Rochester 2GV is stock. I took it apart to look at the jet sizes. Of course there is no stamping on them. I see that on ebay you can buy 2GV jets in sizes from 49 on up and I want to increase the jet size just a little now that I have better volumetric efficiency. Is there a way to measure my existing jets so i will know what size to bump up to? Or does anyone have any literature on the Rochester Jet Size? I have part #s from chevrolet that almost mimic Rochester numbers. The 1971 carb had part # 7002651 and the 72 carb had 7002652. I just wonder if the last number 51 or 52 is the size?

I have most every piece of literature on Vegas and I looked and found every piece of data but the jet size. I don't want to just start buying jets. It would be nice to have a base number.

George in Seattle.

P.S. The 140 runs very strong now with the Opel 4-speed and 3:36 rear end.

[heinz057]

the last 2# are the jet size. example the 52=.052 drill size. hope that helps. also borge warner use to make an adjustable cam gear. i had one on my 72 many moons ago .advanced the cam 4 degreas it realy made a big difference . it was a 4spd with 3.36 stock 2bbl with an edelbrock manifold with a header

[71GTKammback]

Thanks for the reply. I have heard about indexing the cam before but I had only thought it was for the Cosworth DOHC. I wonder where one would get an indexed cam gear these days for the 140 or I suppose I could have it drilled out.

[ColinOpseth]

hey George,
I have a few motors kicking around. If you need any parts let me know. Can't guarantee how good the parts are but I know my '73 non-GT has been sitting since about 1984.
Later,
Colin

[res0o7eb]

Hey Ya'll,

I have been working on "tuning" my 71 Vega GT Kammback for 18 months now. Recent additions are and Offenhauser 2bbl manifold and a period header for the 140 ... It is the original stock 140 internally with 50k original miles.

George in Seattle.

P.S. The 140 runs very strong now with the Opel 4-speed and 3:36 rear end.

George,

You're my kind of guy. I think you and me are 'two of the few' running a Vega 140(or planning on it). And you're near me somewhere in the Puget Sound area! Must be the weather or something. Long live the Vega 140! Someday, I'll have my 140 running in my 76 Vega GT. But, it won't be stock.
Welcome to the forum!

[71GTKammback]

Thanks Man! I have been working 140s since the 1970s. I did just get the new Rochester jets in the mail. They do look just a little bigger than the stock ones so I plan on installing them as soon as I do a complete tune up. My old dwell meter from the early 80s gave up the ghost so I had to go buy a new one. The guy at the parts store was of "Post-dwell" age.

George
Seattle

[71GTKammback]

I had an intermittent miss on the 140 and got out the old multi-meter. Found that the points were actually bad. Replaced those and went one heat range hotter on the plugs. Then I ran the OHM meter on the plug wires and they read 5k, 19k, 29k and 70k resistance. I had heard that 5k-50k was normal. Went to the auto parts store and found the exact Borg Warner plug wire set with the correct vega boots for cheap. (was I surprised) Installed them and the resistance on each wire was only 5k. The engine runs better than it ever has. I have advanced the timing from 6 to 10 BTDC. No ping and it seems very willing now where before it seemed labored. Always nice to have some success when tuning an old car up.

Cheers from finally sunny Seattle.

George