450 size motor to 600/700 size, yeah the wattage will be much higher. Probably 4-8x higher.

If you have the ability with your ESC, try turning down advance timing a bit. The 3 degree, 5, 7, etc. number, not the khz number which is drive frequency and has little impact on motor heating generally, but a lot on ESC heating. The higher the advance timing is the more current the motor will draw through each phase and the hotter it will get (and the hotter the ESC will get). On Castle Creations ESCs I use low advance timing setting which helped keep the scorpion on my TRex 700 in check. Yes, it would and does get pretty hot. Too hot to touch when just landing. This heating is one of the reasons I think Scorpion is insistent on oiling their bearings after every 10 flights, their motors (the bigger size ones in particular) get very hot which will tend to degrade bearing oil more quickly. The quantum and eflight motors I have never get anywhere near as hot, even on similar sized helis.