I don't think it is. I have a 20 hp Gator diesel upon which I have mounted a 6' plow for snow. It does fine, even up steep hills, etc. This plow is geared specifically for snow, though, not for gravel or dirt of any weight. I think you would be fine with your sized tractor and that sized plow as long as you do not care about plowing or grading gravel or hard pack with it. For snow only, it would likely do fine.
John M