You did not say if it will be a v plow or not, I would not hesitate to use a straight blade up to 8'6" on a half ton truck, my concern with v plows on 1/2 tons especially fords, is when you start stacking snow, that transfers, the weight of the plow, plus the weight of the snow,and the force of the motor onto the front axle,
I have an 8'6 vplow on a 92 f250, when I have to start pushing hard and really stacking snow, I can hear the front suspension pop and creak once it bottoms out under the weight. On the other hand, I have a diesel motor, 4 10 gears, and I use 4 low to stack snow so I don't overheat the transmision. This combination will pile snow higher than the truck and keep on going, but does put an extreme amount of stress on the IFS. If you do buy a v plow I would suggest using it on a half ton with a solid front axle where it is easier to reinforce the suspenion, and will also be easier on tires since all travel is vertical, not arcing like on my truck. I try to avoid any serious stacking,and call in loaders to do that.
I think for drives you would be ok using a v plow if that is what you want to buy, since it will let you place snow where you want it. Most drives I push, there is ample room to put the snow with out having to stack it very high.
my two cents