That is expecting a lot out of a single belt to drive that compressor. I would not expect a long belt life. I would also hope the pulleys involved with that single belt drive are in very good condition and can also be easily replaced. Continued belt slippage also wears on the pulley groves because the belts drive off the sides of the "V". When the belt reaches the bottom of the "V" the belt no longer drives anything, it just slips.
Yeah I am expecting issues because of a single long belt and lack of belt wrap. The bracket kit has been sold since 2011 or so, its been out a long long time, but yet I have not been able to find anyone here or other forums who can say "yep I used that exact bracket kit".
The original '69 small block had a single dedicated belt to drive the AC compressor, a whole lot of belt wrap, and belt only went from crank to compressor so short belt too.
