the clutch is new he doesnt think its slipping and he is sure it is shifting i am at a loss the car is not here and i am trying to diagnoss over the phone and do not know what else to tell him
My calculator says 4.56 gears with 26" tires will spin 4123 rpm at 70 mph so you might be right that he installed the wrong gears. 3.54 gears should only turn 3200 rpm at 70.
Only other thing that hasn't been mentioned is maybe the tach is 1000 rpm off?