Probably better than 5. More surface grip area. Wider belt. When Melanie had her 93 Grand Am, I replaced the alternator. It chewed up the belt in 50 miles. The auto parts store gave me an alternator with a 5 rib pulley and one edge of the belt was running up on the shoulder of the pulley. I managed to get back to the parts store before they sent my core in, and they swapped out pulleys from my old alternator.