Can you get em? Does Whipple offer em? All for the 454/502 MAG MPI motors.

No, its to hard on front bearings and friction drive style coupling.

What are your suggestions to extend belt life?

Work more...........boat less

If its any consolation, I used to go through a 10 rib belt on my 525SC at least every season.

I change belts about 3 times a season. If I am going to run hard at an event I change it before hand.

If your going through belts that often, your simply running too small of a OD pulley, which creates more heat on the belt. Then you have to factor how fast the blower is spinning. 3 belts a season is far above normal, 1 every 50 hours would be average. Not much you can do, run a gates belt only, they work the best and last the longest, other than that, there's not much that can be done without knowing all the details. Cog will last far less time and will kill the compressor sooner or later.

Dustin