The max speed for the aircrafts are incorrect.  In the sim, the max speed is 375kts.  However, the real world data is much different.  From Airliners.net:

727-100:
Max speed 1017km/h (549kt), max cruising speed 960km/h (518kt), economical cruising speed 917km/h (495kt). Range with max payload 5000km (2700nm).

727-200:
Advanced 727-200 - Max speed 1017km/h (549kt), max cruising speed 953km/h (515kt), economical cruising speed 865km/h (467kt). Range with max payload 3965km (2140nm), range with max fuel 4450km (2400nm).

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Reference pages are:  

http://www.airliners.net/info/stats.main?id=89  &  http://www.airliners.net/info/stats.main?id=90

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I grew up flying on 727's as we took trips all the time.  I can remember the good ole' days when they would come get kids and take us up to the cockpit.  We could talk to the flight crew and they would show us everything.  We would then get our great Wings pin.  Too bad my kids will probably never have that chance now.  It was the many trips to the cockpit of 727's that inspired me to go to flight school and become a professional pilot.  I flew in the US Coast Guard and then instucted for several years.  Now, I fly just for myself as I find enjoyment in NOT having a boss!  8)

Would be great if you could please fix these speeds in the sim.  I remembered getting from KCVG to KMIA and KATL and KLAX a WHOLE lot faster in real life than is possible in the sim now.  I didn't much pay it any attention until the other day for some reason.  Then when I checked, sure enough, the sim is over 150 kts slower at max.  Thanks much if you would fix this quite large (IMO) problem.

- Greg

Actually, the max speeds are correct.  Airliners.net is wrong, not only that, but flat out wrong.

The speed they show is the TRUE airspeed (or the speed the plane is travelling over the ground if there is zero wind).

Because the airplane is travelling at a higher altitude in thinner air, the INDICATED airspeed is much lower than the TRUE airspeed.  As such, the VNE (Do not Exceed Airspeed) is much lower than most people think since the airspeed indicators work off INDICATED airspeed.  Although, using VNE above approx. FL210 is incorrect as well as above that altitude, the speed of sound is the limiting factor because the VNE is in excess of the VMO (Do not Exceed Mach number).  VMO on the 727 is 0.92MACH, so at whatever altitude that 395KIAS = 0.92MACH, VMO becomes the limiting speed.