I would like to say this about Russell, the guy is a class act I hardly come here and post but I do come and read now and then.
I had some issues with a Go 5pt that I race and I had no luck reaching my local dist so I contacted Russell and he responded to all my e-mails and gave me great advice
After I had no luck tuning with the stock carb ( I even did the LSN mod) I trashed it and use a sirio carb, the down side is this carb gives it a harder punch down low and takes away the smoother acceleration of the stocker but is much more consistent in tuning for me