I have this 800CFM Q jet and would rather use this in my build, but am looking around 900 CFM out of it. I can't find any info on how to get 900 out of one of these. Quadzilla has them, but for that price I would go out and buy a different carb. Can a Q jet guru offer this noob some tips
Ive cut the outer booster rings out of a few and even took the step out of the primaries on 2 800cfm carbs. You lose low speed signal and it may or may not work with a combo its very hit or miss when you start heavily modifying the casting. The best and strongest running carb I ever built and still have in service 10+years later is a 72 350 750cfm unit with outer boosters removed and choke horn cut down and profiled into the throat. Truth be known and stock appearing racers will agree and Jim Rogers has proven it fancy mods dont do much at all other than give you something to play with when your bored on a rainy day
Just mess with jet and rod combos to find what it likes, I have ran no primary rods, just holley jets, ran the Cad carbs with the extra fuel squirters on the primaries, Pontiac tanged rear air doors, etc etc and 99.8% of the time the stock rebuilt one runs stronger and more reliable and consistent
Agreed. When it's all said and done, the stock 800 cfm unit will provide 10 second time slips and feed up to 600 hp with proper modifications. If increasing cfm is more important than performance, cut the outer booster rings out, and open up the primary side air horn. Remove all choke components. You can even modify the baseplate to have larger primary throttle blades. When I build a race unit, I do clean up all the casting marks in the main body, and open up the primary side of the air horn as much as possible. I don't have access to a flow meter to measure the cfm, but the quadrajet still has good driving manners and excellent track performance.
I do want to retain the performance of it. I will stick with the stock unit at this time. I will have to buy a book on how to rebuild these. I have rebuilt 4GCs and 2GCs but this will be my first Qjet. Thanks Guys
Good move IMHO. Before heavy modifications like removing the booster rings make sure the application is really going to need that much CFM. We have legal Super Stock cars into the 9's with the smaller 750 castings that have never had a grinder or sanding roll touch them! Even so I see folks hacking the rings out of q-jets for engines that aren't going to make 400hp and vehicles that'll never get out of the 13's unless you drop in out of C-130.........Cliff
