Fred - just reread your post about your friends duals. We try to suggest when using dual 1 barrel carbs that the owner use either (A) carbs with a mechanical power system ie Carter W-1 on pre-1949 Chevy 6; or (B) carbs with a vacuum power system which were designed to run in a multi-carb environment ie Carter WA-1 as used on Hudson Hornet Twin-H power. While other carbs such as the type B Rochester can be used, tuning becomes a nightmare due to the lack of different tension vacuum springs. Due to demand, we finally had to have different tension springs wound for the Rochester 2G series (2 barrel), but have never done so for the B. Typically, running 2 (or more) Rochester B carbs will have the power valve open at high vacuum. The owner then will downsize the main jets to compensate, and wonder why it runs lean at WOT.
Jon.
