pb,
Of course you an do that, cut those ribs off. But ask yourself why they were there in the first place before you do. PSI on the snow will change dramatically with 36' of width gone. Your machine may perform more like a boat anchor than a snow cat. The 240 hp diesel and hydo's are heavy and only give maybe 40% of HP to the tracks. But they are easy to operate, and perform well in all conditions. They can spot turn, big deal when working...The penalty is the width of tack nessary to carry all the extra weight.
Get your machine weight, and measure the track square incehes on the ground and divide it out. A good number would be 1.5 psi or less....
Hope this helps, Kirk