My situation is, in the 79 half ton, I've replaced the Varajet once a few years ago, and I am not happy with how it is running. Seemed to slowly run worse as time goes on : Runs rich, floods easily when warmed up, worse gas mileage on the highway. The old varajet it came with was no great shakes either. Why I changed it. A friend has suggested I try putting a classic Two G "2-Jet" which I think were on mostly V-8 s.. I have picked one up at a swap meet, with no identifying tag. I'd like to rebuild it if I could determine the right kit for it that might work with the inline 250 displacement. Also a source for an adapter plate. Does anyone have experience with this combination? I've searched here, can't find a definitive opinion on it. Also, I wont be mentioning dealing with the myriad smog stuff on here, because of forum policy. The holes at the bottom are 1-7/16. Thanks for any ideas here! Charley By the way, I have the filter and the fitting for it. I will open it up soon to try and determine some internal characteristics.
~Charley 1954 Chevy 3100 with 235 261 project engine “Ole Blackie” Follow along in the DITY 1963 Chevy half ton stepside short box 230 1954 GMC 3 ton 302 And several more Chevy camper and work trucks 1979 1987 1996 1931 Packard car, 327 i 8 auto
Do you have the machine tools available, and enough experience as a machinist to make the carburetor fit the manifold? An adapter plate is not a good option. The carb to use, if you can find one, is the small bore Rochester 2 barrel used on the 265 and 283 V8's, not the bigger bore 2G series that was used on the 305 engines. As always, "The ABC's of carburetion are- - - -Always Buy Carter!" That was true in the 1950's when Carter made a direct replacement carb for the Rochester B. and it's still true today. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Thanks Jerry. No I can’t do the machining. The small bore two barrel Rochester you mention, I thought that’s what this was. So, smaller bore than the 1 an 7/16 that this two jet measures? And, I’ll look into a Carter replacement, as well. I would love to have a simplified and good functioning carburetion system! I wish Carter offered the same direct replacement for the Varajet. I hate to try rebuilding my old one again. National Carburetor did the last one and I was less than impressed.
~Charley 1954 Chevy 3100 with 235 261 project engine “Ole Blackie” Follow along in the DITY 1963 Chevy half ton stepside short box 230 1954 GMC 3 ton 302 And several more Chevy camper and work trucks 1979 1987 1996 1931 Packard car, 327 i 8 auto
I'm not sure about the throttle plate size, but the 2 barrel used on the 265 and 283 engines had smaller throttle bores and venturis than the ones used on the 305, 327, and 350 engines. They give better throttle response and fuel economy than the bigger bore carbs, especially if they're used on a small displacement engine like a 250 or a 261, etc. For instance ;
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Yes , it’s true. The Integral. So, I have plans when I get time, to do the head swap. Since the forum has included these later trucks, I haven’t seen a lot of activity on them here. The head will be another thread.😀
~Charley 1954 Chevy 3100 with 235 261 project engine “Ole Blackie” Follow along in the DITY 1963 Chevy half ton stepside short box 230 1954 GMC 3 ton 302 And several more Chevy camper and work trucks 1979 1987 1996 1931 Packard car, 327 i 8 auto
The integral heads are OK as long there is no heat cracks or exhaust leaks. With the two barrel, they actually run decent. The problem with swapping carburetors that require adaptors, is the adaptor itself is a strong choke point. Even if the carb going on is a good one, the adaptor will likely kill the benefits of the better unit. If you get shape it right and minimize the miss match, you might get away with an adaptor, but the best bet is a better stock carb than you have, then it will bolt on and be calibrate for the engine.
Thanks,Joe. I will be posting what I wind up trying. I appreciate the word on the adapter, HRL has said similar. By the way your beautiful 37 has a 250 I guess. Nice truck! C
~Charley 1954 Chevy 3100 with 235 261 project engine “Ole Blackie” Follow along in the DITY 1963 Chevy half ton stepside short box 230 1954 GMC 3 ton 302 And several more Chevy camper and work trucks 1979 1987 1996 1931 Packard car, 327 i 8 auto
The 2->1 adapters work about like merging two lanes of heavy traffic into one lane.
At low speeds (RPM), not a problem.
The higher the speed (RPM), the worse it performs.
Zenith made single barrel carbs in the size 3 throttle with both larger venturii, and smaller venturii than the varijet, depending on your desires.
All of the Zeniths are (opinion) more reliable than the varijet. Some come with an externally adjustable main metering jet. Some come with an adjustable throttle arm.
The bad news: they don't cost the same as a varijet (wonder why ).
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
The carb pictured is the small bore carb. I think it would take quite a bit of engineering to adapt it to the integral head. It would be easier to go ahead & put the external manifold head on it. The external man. head was also available on later models Cameros & Novas.
George
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne Super In the Gallery Forum
Thanks Jon and George, I will work on this. Good info.
~Charley 1954 Chevy 3100 with 235 261 project engine “Ole Blackie” Follow along in the DITY 1963 Chevy half ton stepside short box 230 1954 GMC 3 ton 302 And several more Chevy camper and work trucks 1979 1987 1996 1931 Packard car, 327 i 8 auto
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