there is a gates I used inplace of the 166 until the 377 came out. It was slightly shorter than the 166.
Here is what gates recomends now, from the gates site:
http://www.gates.com/part_locator/index.cfm?location_id=3002
Product Detail
Product ID
98390039
Part #
43X4320
Product Description
43X4320 XTREME SNOW BELT
UPC
072053841381
Category Hierarchy
Industrial Power Transmission -> Heavy Duty V-Belts -> Snowmobile Belts -> Xtreme® Snowmobile Belts, P.N. Series 9839
Automotive -> Belts -> Snowmobile Belts - Xtreme®
Product
Application
Features/Advantages Withstands temperature extremes down to -30°F.
Aramid Tensile Cords combine limited stretch, extraordinary strength and durability.
Markets/Applications Designed for snowmobile trail rider and high performance racing sleds.
Belt / Sprocket Specifications
Angle 26
Category Name Description Aramid cord and advanced composite construction provide extraordinary strength and durability for high performance requirements like power clutching. Also well suited for everyday trail riding to produce long wear and dependability.
Effective Length (In.) 43.37
Effective Length (mm) 1102
Outside Circumference (In.) 43.37
Outside Circumference (mm) 1102
Recommended Sheaves Contact the Gates Made-To-Order Metals Team.
Top Width (In.) 1.438
Top Width (mm) 36
Notes
Belt Notes Length listed should be used for length comparison only. If a cataloged belt does not fit the specific snowmobile, use the reference length to determine if there is a slightly longer or shorter belt length available which meets the manufacturer’s belt fit specifications.
Packaging
Standard Pack 30
Product Attributes
Notched Yes
Specifications
Length 44.000
Weight
Weight (Lbs.) 1.45