Build Yourself A Stage3 727
As you know there are a number of systems on the market to reduce the level of noise that the 727 produces. The 727 is only just stage 2, In fact it is quieter that the 757 during the approach in most cases. You can spend a bloody fortune getting one of the pre produced solution's on offer or do it DIY.
To get the little sucker to comply we need to attack the following areas Take Off and Final Approach. These are the two points that it falls down on.
Now providing you are willing to accept some performance reduction in Max Take Off Weight we can easily get round the first problem by the following.
These should bring you in limits for the take off, adjust the climb power as required
As for landing, simple use flap 25 and use the flap override switch at some point after gear down and above 250'. (Mode 4B warning). Add 5 knots to the Flap 40 Vref calculation. You can replace the cam if you want that schedules the GPWS to make flap 25 a landing flap.
Write your own appendix to the flight manual and get it approved. Know your reg's and what you can and can't do !!!. Just saved yourself $ 600k at least.
I won't go into this to deeply as it will upset a few companies that are making a killing, I will communicate on the topic off web if you want.