[Cliff R]

I could literally put up 100 pages here with direct examples of how this deal really works. Instead, I'll simply say that no matter what carburetor you choose to power the BBC truck, tuning it exactly for the application will yield pretty decent results, power, fuel economy, etc.

Having a good working carburetor goes a bit further than just fuel economy, you should have a working choke, fast idle, dual plane intake, moderate compression ratio, and very well chosen cam to get the very best mile per gallon, power, and driveability from the truck. I would also have an open exhaust crossover in the intake, unless you live on or near the equator, then it really wouldn't be needed.

As far as this specific topic goes, I've actually causes the demise of quite a few TBI set-ups on Chevy/GMC BBC and SBC truck applications by swapping them over to q-jets, outrunning them at every rpm and getting considerably improved fuel economy as an end result.

I'm probably not as brand specific as most folks think. I've ran the gauntlet with Holley's, Demons, Carters, and Thermoquads. The Thermoquad and Q-jet are ALWAYS going to be more efficient at the end of any tuning efforts. It's just a better design on the primary side, and not all about having smaller primary bores. The venturi areas are super-sensitive to throttle position and pressure differential above and below the throttle plates and venturi areas. They not only pull in fuel much earlier than a large bore carburetor, they break it up into a much finer mixture, usually referred to as atomization. Later q-jets also use a fine metering system providing the user/tuner with full control of part throttle A/F without taking the carb apart or changing any parts. That deal alone will trump any other brand.

Qjets are also very reliable in long term use. No gaskets below the fuel level to leak, fuel bowl/float in the center, jets on the bottom, and excellent bowl venting.

If I were setting up a BBC truck engine it would get a q-jet, it would be a 1979 or later side inlet Chevy style with the single main airbleed design. These are very well made units, taking all the good points and upgrades from early designs and putting them into one package. They all convert and many came with electric chokes, relatively compact design, and over 800cfm airflow if/when needed. It's going to have a PCV port, power brake port, vacuum port for the distributor, and the correct location/geometry to hook up the throttle cable and return spring(s). Below is a picture of a finished unit. I've built several thousand of them since going full time here over 11 years ago. Can't even remember having an issue with one of these, or getting one back for any reason. They just flat work, while being super efficient, easy to tune, dead solid reliable in long term service, and the best choice for what you are doing....IMHO.....Cliff