Yep, there are a few guys running 10's with a Q-jet. Killer fuel systems, 1/2 line, and modified internals. I've modified some of those carbs, knife-edged the blades, ground out the fuel bowl for more volume, modified the secondaries to use jets, cut out the primary ring boosters, etc. They aren't stock Q-jets.
And for every car that's running 10's with a Q-jet, there are about 1,000 guys running 10's with a Holley.
I ran 11.60's in street trim, full exhaust, street tires, 2400 converter, 3.42 gear, with an Edelbrock 850 Q-jet. And I too used pump gas, although the 93 octane variety. I played around with a Holley HP950, and out-of-the-box I encountered severe traction problems under 40 mph, something I never had with the Q-jet. I went back to the Q-jet because I drove my car more on the street. I currently have a Holley 3-barrel. For a 40-year old carb, it runs like a champ.
Factory cars, oh oh, this is near and dear to me.
The factory Pontiac RAIV used a Quadrajet. When the engineers designed the ultimate 400 engine, known as the RAV, higher revving, with huge ports, they chose the Holley 780. That went completely against policy. GM used Rochester carbs exclusively, so this was not a minor change. Pontiac engineers designed a different air cleaner base, they would require all new Service Manual Supplements to be printed and sent to all Pontiac dealers on how to tune and maintain Holley carbs, all the mechanics would need to be trained on a new type of carb. Plus, GM was tight on their warranty issues, so allowing a part from an outside company to sit on top of one of their Pontiac engines was not to be taken lightly. Obviously, Pontiac engineers felt pretty strongly about using a Holley. It made more power, and they knew the RAV would be on race tracks.
Others
The 1970 Chevrolet LS5 454 used a Quadrajet. The top of the line, highest horsepower Chevrolet was the 450hp LS6, which used a Holley. 1969 Chevy 396 and 427's used a Quadrajet, but the 427 high-perf models, including the L-88 and ZL-1, used a Holley. They also used Holleys on the tri-carb L-88 model, odd considering Rochester had 2-barrel carbs stacked up from the old Pontiac and Oldsmobile programs.
1969 Ford 428CJ used an Autolite carb. The monster Boss 429 Mustang used a Holley. All Ford race cars used Holley carbs, including their 1969-1970 Boss 302.
The 1970 Buick Stage 1 used a Quadrajet. Buick's racing engine was the Stage II, available over the parts counter, which used a Holley.
Mopar wanted to use Holleys on their 1966-1971 street 426 Hemi, but the intake carb spacing wouldn't allow the Holley float bowls to clear. Their street engines used Carter carbs, the racing engines used Holleys.
Pontiac SD-455 was designed with a Holley, but due to emissions requirements, they were straddled with a Quadrajet. When the engineers prepped an SD-455 for competition, and to see how much power it would make on the engine stand, they used a Holley.
