on BDL website the have a chart that will get you what you Ned as long as you have front and rear pulley tooth count and center center distance of trans out put shaft to your rear axle.

 

I realize this is an old thread but people still end up on these older threads when doing a search. So for those like me who are searching for belt length info, here is a good starting resource: How to determine your belt lenght - RJC Choppers (rjc-choppers.nl). I hope this helps someone