Problems after Cylinder head Port & Polish

Did you polish the intake ports also? If you did this could cause less atomization of the air/fuel mixture (less turbulance than just a porting/mixing job) and cause it to puddle in the intake ports near the intake manifold which would mean you'd have to run it rich for any air/fuel to get into the combustion chamber. For the puff puff sound i couldn't tell you and for the rich smell, you may just have to run it rich if this is the case. Good luck