First off, I´m not a mechanic. I couldn´t tell you what kind of HP changes you could get or anything about different stages. However, I do know that the carb models changed every year they are all very similar in the 1978-1987 cm/cb series. (models VB22A {stock} VB22B, VB22C, VB22E etc.) The only thing that really changed was the jet size and pilot screw setting, the bodies didn´t change. I can´t imagine not being able to run off of a different carb providing that carb is NOT for a hondamatic (cm/cb400A). I also know that you can buy complete carbs from ebay for as little as 30$... worth a shot. Hope this helps. If you decide to do it, post your results. They would be an interesting reference for others.