Rochester carbs are a bit of a challenge to get set up on a multi carb intake. Not impossible, but its a good bit of work. The very best outline of how to do it was written quite a few years ago by Pat Smith for Inliners. Pat was Dyson Racing's Crew Chief for many years, taught automotive mechanics, lots of stuff. Is one of the best mechanics and problem solvers I had the pleasurer of being introduced to. Here is his article:
https://www.inliners.org/tech/tech4.htmlAs for the unisyn, you are not using it to adjust air fuel at the air fuel needles. You are using it to get the throttle blades in the same relative position so that each carb is taking in the same air at idle. Essentially, you want to make sure the throttle blades are not exposing the off idle circuit at idle or that one of the carbs has a throttle blade that is exposing the off idle circuit at idle. Otherwise you end up with the carbs going in and out of idle to off idle to idle and back to off idle as one carb leads the other in and out of the idle off idle circuits. So start by setting air fuel needle screws about 1 and a half turns out from bottom. Disconnect one of the carbs from the throttle linkage. Get the motor running. Install the unisyn on the carb with the linkage still attached. Get the ring centered in the vacuum tube. Now move it over to the other carb. Adjust the idle speed screw in or out until the ring is in the middle of the tube so that both carbs are now taking in the same amount of air at idle. If the idle is too high, turn the idle speed screws out (both carbs, a little at a time) or vice versa until you get to the lowest idle speed the motor will maintain. Double check each carb with the unisyn. Make adjustments if necessary. Now you can tinker with the idle mixture screws to get your best lean idle. Not an easy task with these Rochesters. Adjusting the idle mixture screws may very well raise or lower the idle speed. Readjust the idle speed screws as necessary to get the idle back to your idle speed. When the air fuel mixture is adjusted, recheck the carb with the unisyn.
The other alternative is to get a couple of adapters from Tom Langdon, and purchase a pair of 1974 ford pinto carbs (Holley/Weber 5200). Nice progressive carbs, run great out of the box and dial in way better then the Rochesters.
