I have a full python exhaust and a arlen ness big sucker stage 1 on. Should I still back out the mixture screw 2 1/2 - 3? I have a 48 main. I have it backed out 1 1/2 right now.

 

48 pilot/idle jet?

 

Pilot yes sorry, was writing fast

 

Backing it out will richen the 'no throttle' fuel. What this would normally fix is exhaust popping on deceleration; so if your getting that symptom then by all means back it out a little more.