I have a 2002 lightning with minor mods. I have dual flowmaster exhaust and a K&N filter. I just bought a 5# lower pulley. Is than to much and do I need a performance chip or anything else?

 

I'd get a chip, filter, traction bars, and driveshaft loop.

 

I would have the truck dynoed with the pulley on just to make sure the A/F ratios are safe. Stay out of the boost til you get this done. I know some people run a 6# lower with no chip but that's like russian rhoulette.

 

Get a chip...