Always best to provide a link to the item you are asking about rather than make us look it up.
You say you tried a 280 watt motor, but did you put a wattmeter on it to see if the prop/battery combo you put on it drove it to 280 watts? Just because a motor is listed as offering 280 watts does not mean it will hit 280 watts with any prop and battery combo.
Is this the motor you are asking about?
http://www.horizonhobby.com/park-450...890kv-eflm1400
According to this document, the 450 is a 175 watt motor when run with the right prop on the right battery
http://www.horizonhobby.com/pdf/EFL_..._Motors_Ad.pdf
Based on that chart the Park 480 BL, 1020Kv is a 275 watt motor when matched with the right prop and battery.
The Power 10 BL, 1100Kv EFLM4010A is rated for 375W when matched with the right prop and battery.