Bill, good luck on finding much information however:
Since you do have an adjustable main metering jet, you can play with adjusting it.
First, since the vehicle is running, you need to know what setting you are currently using (somewhat of a "base line"). With the engine off, gently turn the adjustment in until lightly seated, counting the number of turns. Now return the adjustment to its present setting.
Start the vehicle, and run the engine until fully warmed. Now drive the vehicle at your normal cruise.
If the engine does not "surge" (feels like a miss, or you are constantly being buffeted by a head wind); stop, and readjust the adjustable metering jet by turning it in (probably clockwise) 1/8 turn. Repeat the driving test and readjustment until you experience surge. Then back the screw out 1/8 turn.
If the engine surges on the current adjustment; back the screw out 1/8 turn at a time until the surge is gone.
ALL OF THE ABOVE assumes that the engine has good compression, and that the ignition is in good condition.
And lastly, would suggest you look for a different carburetor OR even give another look to your old Rochester B.
Jon.
