what is a good length /90deg or 60deg for a mach1 with 196 studs I'm not a real agressive *rider *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/confused.gif 6 inch or 9 inch

All those studs are going to bite pretty hard. I'd go with the 9" carbide at 60 degrees. Check out Woody's (http://www.wiem.com/intro2.htm) They have recommended configurations for studs/carbide.