The Q-Jet is a great carburetor!
HOWEVER: one needs a manifold for the Q-jet to fit.
The 216 was rated for 3400 RPM
The 235 was rated for 4200 RPM (1956 and newer)
The 261 was rated for 4000 RPM
The 230 was rated for 4400 RPM
The 250 was rated for 4200 RPM
The 292 was rated for 4000 RPM
DO THE MATH! Mathematics truly IS your friend!
CFM = CID times RPM times volumetric efficiency all divided by 3456.
These 6 cylinders have a volumetric efficiency of maybe 70 percent (0.7).; BUT WAIT (as the infomercials say). Lets say you port the head, put in a full-race cam, put in domed pistons to get the compression ratio to about 10.0, add racing headers, and some form of super ignition system and get the volumetric efficiency up to 80 percent (0.8)
For the 235 with ALL the mods above:
CFM = 235 times 4200 times 0.8 all divided by 3456
CFM MAXIMUM is 228.
For the 292
CFM = 292 time 4000 times 0.8 all divied by 3456
CFM = 270
Note these maximums are the RPM limit for a highly modified street engine.
Now, if want to balance the crankshaft, machine high strength rods, etc., and turn these engines into race only; you may be able to obtain more RPM.
Both Stromberg and Zenith offered one-barrels that will bolt directly to the 235/261 manifold that are rated 215 CFM, and, while not readily available, Zenith offered a larger 1-barrel that was rated at 252 CFM.
Note that the maximum CFM in the illustration above are for wide-open-throttle requirements at the maximum RPM.
With no offense meant to anyone by my next statement:
If a two-barrel or a four-barrel equals "cool", then by all means go for it; just don't expect any great performance increase, and you might just LOSE performance at normal city or cruise RPM.
Oh, and bztguy, the Q-Jet on an engine which can handle it, works great on the strip. They even can be made, although with some difficulty, to go around corners for that form of racing.
Jon.
