for normal city driving... right now i'm using a 2 bbl on a stock 350... and my mileage sucks... less than 12 mpg's...damn...

 

A spreadbore 4 barrel with primaries smaller than the 2 barrels bore

Daz

 

I suppose you could take your existing carb (a Rochester 2GC?) and try different jets and rods. Also, plug up the EGR and experiment with the mechanical advance springs in your distributor. I'm assuming it's a GM HEI. The existing advance curve may be too fast. An adjustable vacuum advance is worth every penny for fine tuning!

The older two barrels aren't as efficient as Q-Jets and Dual-Jets for regular street driving, but you should be able to squeeze out an extra 3 mpg with some fine tuning as mentioned above.

 

I agree that you might have something else going on that is causing your poor gas mileage. One of the most common is needing a tune-up. If that's not it, the next is a malfunctioning vacuum advance. Other than saying you have a 350 w/2bbl, you didn't give much more info, such as transmission, gears, etc.

I will also agree that a q-jet will give better mileage, if you stay out of the secondaries, than a 2bbl Rochester. I have converted two engines from 2bbl to q-jet, a '70 Impala w/400, and a '79 Caprice w/305. In both cases, the car got better mileage after the conversion. IF those huge secondaries weren't opened, that is.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

thanks guys, the car is an 83 t/a with a 700r4 tranny(?), it has a posi rear end (don't know the ratio though)... the 350 came from an 87 i think, the carb and intake are the older units(don't know the year)... it doesn't have electronics and stuff... i 'm gpnna try getting a q-jet without the electronic stuff.. it's hard to get stuff here in the philippines...