Key word here is 'efficiency'. If you can improve air velocity into the head it will help. All of the port work you're thinking about doing is aiming at making the engine more efficient. The story goes that 'the total power/energy created is greater than the sum of parts' when it comes to engine building. A port that isn't flowing right or a valvetrain component not working at its potential robs energy from the rest of the engine as everything else is trying to compensate. If you have a look @ LSRMike's pics you'll notice that the casting shrouds around the valve guides have been completely ground down to the gallery walls - this really improves velocity and flow into and out of the head but it requires the valve guides being removed. Is you coil in good condition, exhaust flowing nicely etc? What is your tune like? Might be another reason why it's falling on it's face...