I have seen some threads on that in the past. Seems like people were having trouble tuning those carbs and not having the tech support from Tom Langdon that they wanted. However, he has been great at getting ahold of me and helping out.
According to Tom, the Holley/Webber has a higher cfm rating than the Carter/Webber versions. I felt the 235 was being starved, which is why I wanted the Holley/Webber. However, the benefits are limited with the funnel-type adapter that you have to use. I think if I really like this carb, I might alter the intake to accept the entire carb rather than use the funnel adapters. That way, the benefits of all the higher cfm can be realized.
Operation is DEFINITELY better than the Rochester 1bbl, however.
