every one says to not put on the alt pulley but i have had no problems with the jet crank and alt pulley. on my firebird...
what gives?

 

Welcome to the board! Don't believe everything you hear, if it worked for you, great!

 

I think it's just because some people with the original alternators have tried the alt. underdrive pulley and it turns the alternator too slow...and because the alt. is old and not putting out quite enough, the car starts to draw power from the battery. A low idle speed could also affect the alt output but I doubt it'd be that significant.

I've heard both sides of the story man, but like Tom said, if it works then why not? As long as your alt is putting out enough power! Just don't try to run any big power draws like stereo (amp, subs, etc.) without getting a higher output alternator.