I have been reading over old quadrajet forums and have been reinspired by there gas saving ability along with what seems to be endless things that can be accomplished with them. I have to carbs one a quadrajet and the other is a holley quadrajet replacement it is a squarebore carb also. I am trying to decide what to use the quadrajet I have on right now needs to be rebuilt I was wondering if the holley replacement carb could get as good of MPG as the quadrajet? I also would like to know what would be the smallest primary jet size to go with on either carb to get maximum power and MPG also? It is a 383 with a comp cam with .454 lift?
Thanks for all the help Guys!

 

Jetting for maximum power isn't the same as maximum mpg. Every engine is different so I would hate to guess a jet size. Running an engine lean can melt it down(overheat). Bigger engines use more fuel, so your 383 isn't going to be a mileage queen. Both the holley and q-jet, set-up equally will give you about the same mileage and performance.
Q-jets are spreadbore, so I assume you are talking about a spreadbore holley.
The carb is just part of mileage. Ignition timing, good ignition parts, proper jets, gears, right foot pressure, aerodynamics, ...

------------------
82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro