i just bought jdm headlights to put in my hatch but the driver side wont fit because the alternator is to close to the lights. the jdm headlights are longer than the usdm ones so i was thinking bout getting a shorter alternator belt. what size belt could i use?

 

First, make sure that just gettin a shorter belt would solve the problem.

Second, just go an inch shorter on the belt number and see if that is good. If it doesn't fit, go up .5"; if it's not enough, swap out the belt for a slightly smaller one.