My polaris sleds had limit straps under the skid set to tight. If you loosen these up as far as they go, by the nut on the strap, or by moving at the attachment to the farthest position, as you gas the sled, it allows the sled to rock back on the track and limit the snowplow effect.
Sorry for the poor explaination, but without looking parts list up, it is the best I can do...but believe me the sled will behave much differently if you do this...in powder.
The trade-off is that is won't hold the corners at high speed on the trails.
And as Polarisrider says, put powderpros on there, as Polaris skis suck at almost every thing you want them to do....save for lake racing.