I was kinda thinking the gear should go the other way but a great converter can make up a lot. If it were me, I would use a 4.56 and shift it at your 5,300 and hope it goes 6,500 through the lights. It probably won't though. Most Stockers are in high gear before the 660 but 4.88's and 5.14's probably are a bit much for most guys. It's expensive to really optimize 60' times. Guys have 4-5K of converters laying around. Center sections are not cheap either.