Russ,
There a couple simple things to look at before you make any changes. Look down the carb with someone stepping on the gas pedal[engine off] and see if the secondaries open all the way. Also with a mild cam the power may die at 5000 rpm and you are wasting 3 or 4 tenths in every gear , I know my car runs quicker by short shifting the gears.
Good Luck,
Perry.
