The Q-Jet can be made to really run well on most applications, depending on the skill of the individual doing the tuning. MOST are 750 CFM, which is a fixed 150 on the primary side, and a "demand" 600 on the secondary side. So if the tuner understands what he/she is doing, the secondary will only supply what the engine asks for. Virtually impossible to overcarburate.
To anyone even considering using a Q-Jet, the paperback on tuning Q-Jets by Cliff Ruggles is absolutely required reading. One of the most user-friendly carburetor books I have ever read, and don't need a college degree in mathematics and physics to understand the book.
Jon
