The mono-jet has a vacuum controlled metering rod,in the same order as a Q-jet. I have played around with the power piston spring on a 1972 model while running it on a '69 230. I have not run a mono on anything other than a 193-292 series motor either, but see no problem if rebopped per Doug Roe's Rochester book explains. I do believe that the 292s had a big 1-11/16 butterfly and 1-5/8 venturi in a mono version also. And the mono-jets dont make that wimpy whistle noise at part throttle accelleration.
The varijet would be neat if you could make them work right as the design, in principle, is like that of english SUs. But I too never had enough interest to bother one.
