Spud
The Iranians are very good at adapting all sorts of things to fit - here is an open source picture of a Hawk Surface-To-Air Missile (SAM) that was adapted to be fired from an Iranian F14.
Also, if carrying some "lash-up" like that above, a speed of 350kts may be quite reasonable if a full envelope trial has not been done. Furthermore, pulse-doppler RADARs are good at measuring speed in lock, but not so great in search - the aircraft could be doing 300kts but the RADAR shows 350-400kts whilst tracking it in some form of wide area tracking mode. Finally, engaging at min range would not help as anti-ship missiles have a long range - even smallish ones like Excocet (remember the loss of SHEFFIELD? It never saw the Super Etendard).
Get the picture?
LJ