factory track is 116 on the 89, 121 on the 90 if your years are correct, the 90 is a phazer 2 right? you can put a 121 cheap used track off somethin, shorty rail extensions from WPS, and dont bother with the tunnel extension on the 89. just hammer the flap mount back a little. lot less time than extending the tunnel and about the same performance. id get plastic skis too, the steel are heavy and hold the sled back in potential. if its clutched right for stock, just wind the sec. spring up a notch or two with the new track.