IO540
Not strictly true, unfortunately. Stall is exclusively a function of angle of attack, and the angle of attack can cause a stall at above book speeds for your configuration for a number of reasons.
The best known is being in a turn, which can dramatically increase the IAS at which a stall starts, but high speed stalls can also be acheived in any aerobatic manouevres which use inertia to move the aircraft in contradiction (as it were) to aerodynamics.
Also various wind conditions (notably microbursts) can cause the angle of attack to increase (because the airflow is coming from a different angle) despite the airspeed being kept constant.
It is for this reason that bigger/faster aircraft use AoA measurement rather than IAS to determine closeness to stall.
W