The Q-Jet was designed by the Rochester Div of GM.
They pulled out all the stops in carb design at that time, because
of the lurking EPA shit that started in the 70's, before FI came out.
All the stops, means they designed the Q-Jet to be one of the best
metering carbs ever made. Which it is .........
However in the early days, most hot-rodders did not understand the
complication of the Q-Jet, vs the more simple Holly design, which
became a favorite. Hence the reason that the Q-Jet got the bad
press of being "Quadra-Junk or Quadra -Crap".
Carb Mike took it upon himself several years ago to learn about the
Q-Jet and received his "PHD" in knowledge, which lead to his
sucess in making them work like they do.
As FI came on board, Rochester Division of GM sold the rights to
manufacture the Q-Jet to Weber. I believe the Carter Design AFB
was also sold to Weber, that is what the V8-Choppers use.
Edelbrock sold both of these, with their name, until sales went into
the trash can several years ago, at which time they quit selling the
Q-Jet design, but still sell the Carter - AFB design.
That is the reason BH went to the Demon Carb, which is owned by
Berry Grant.
The Demon is a very good carb, but they did have a few small quality
problems at one time. The Demon is basically a jazzed up verson of
the Holly design, that flows better due to body design. A 650cfm
Speed Demon will flow about 750-780 cfm, but all the crisp throttle
response of a small ventura carb.
Carb tuning many think is a "Black Science", but once you understand
them , all the dots fall into line. Especially with the tuning tools
currently available like the Wide Band o2 sensor set ups.
Reading plugs accuratly is just about impossible with the new gasoline we are using.
Remember all carbs no matter who makes them, will come rich from
the factory for liability reasons. Fat is happy - Lean is mean. Too
lean will hurt ya......
![lol :lol:](./images/smilies/th_lol.gif)