Senior Tech Team
Join Date: Apr 2012
Location: Yerington, Nevada
Re: Holley 4780-2 or Q-Jet 7040202
780, 800 cfm, all depends on the vacuum depression the carb is flowed at. In essence, Holley didn't like the odd flow rates of the LIST-3310 carbs when they went into after market sales, so, they did what Chevrolet did earlier with the 302 Z28 engines, they simply flowed to get 750 cfm, and stopped. In the case of the 302, and a lot of the big blocks, they went to a set horsepower, and stopped going any higher. The 302 was restricted to FIA racing regs for its class in road racing to 305 cu/in maximum, and 300 horsepower, so, it made a solid 302 cu/in and was rated at 295 horsepower, although it made more power over the rpm level it was certified at.
We saw both 396 and 427 go to 425 horsepower, and, the 396 between 375 and 425 horsepower. These were factored to have a set power level, because of insurance regulations and limits too many horses, no insurance. A ZL1 was rated at 430 h/p, but a good one made roughly 565 h/p.
It was a sales numbers game, nothing else.