JW ,
HotRod,
I think I remember from past discussions that you are a proponent of the Q-Jet. That said, I don’t know how that carburetor would be less prone to heating than the Edelbrock I now have.
The imitation AFB you have is aluminum, and while the imitations are permanently banned from our shop; I have two GENUINE Carter AFB's on my non-Chevy shop truck. After shutdown of a hot engine, BOTH are bone dry within an hour (percolation, and evaporation). The imitations are worse. I use an electric fuel pump.
The Q-Jet does have an aluminum throttle body, but the rest of the castings are zinc (different rate of heat transfer) plus there is an insulating gasket between the throttle body and the rest of the carb.
The Q-Jet (opinion) is one of the two finest carburetors ever built for a single carb application on the street (the Carter TQ being the other).
As mentioned previously most Q-Jets are either 750 CFM or 800 CFM (there is also a scarce and expensive 850). But one has to understand these CFM numbers. All three have a variable 600 CFM on the secondary side; but the primary side of the 750 is 150, of the 800 is 200, and of the 850 is 250.
The primary side of the original RACE only 283 carburetor I mentioned earlier is about 200, the street version about 175.
Contrasting that, your imitation is approximately 250 on the primary side (much lower venturi air velocity).
When considering 4-barrel carbs, it is important to consider primary CFM / seconday CFM as well as total CFM.
Jon
