New pullies

[TurtlesRun]

Ok im on vaction in vegas right now fun as hell right..... just thought i would let yall know, but anyway my uncle came across a set of bbk aluminium underdrive pullies for my 88 mustang he said he thought about me and paid 25 bucks and said it was no skin off his back to give them to me... brand new in box never used. says it increases horsepower 15-20... but i highly doubt that... why would someone sell so cheap is it a shit mod, not worth my time to put on my car, i looked at a few spots and they said once installed can give me a problem with the alternator charging my battery or some crap like that.. anyone have any input on these pullies i mean they were free so why the heck not.. on the other hand if they give me problems than its not worth my time. let me know yalls thoughts

[SeeingRed]

You'll be alright. If you're running subs or have a weak alternator, your headlights will surge at idle when they're on, but other than that you won't even notice. And you won't pick up 15-20 hp. Maybe 5.