alternator belt

I put the power master alternater on my stroker last year, and had the same problem. They come with a pretty shallow groove pulley. These strokers rev so fast you could watch the belt stretch and fly off. I had the pulleys aligned so close i swore up and down that wasnt the problem, but i shimmed it until they were aligned perfect and still had the problem. My fix was to find the shortest belt possible, switch to a Moroso deep groove large diameter pulley and tighten the belt to the point it makes me wonder when ill need to replace the bearings.:scratch: