underdrive pulleys?
reduction in parasitic loss from the accessories, which means more power to the wheels.
cons:
possible reduction in Alt output when under load. so if you have a system...i woldn't bother
Trending Topics
The Best V8 Stories One Small Block at Time
The SLP unit has deep grooves and Ive been running on a stock tensionier for a while with out any thrown belts.
I got mine from SLP, they had everything there and fit perfect. The belts were just properly measured, you can obtain those at any local auto store as long as you know the length.
Also no ALT pulley, no charging issues.
Here is one installed on our 240 amp alt:

They come standard on the alt.
Also, the tensioner pulley has higher outer ribs to help retain the belt at high RPM's:
http://www.gmfullsize.com/forum/showthread.php?t=106041






Anybody ever weigh a March UD?? price was good about $190 SDPC.