I have a Narragansett wire harness. It seems to be high quality, and I've been pleased with my choice. There were issues with the order, however. In the end though, everything was resolved to my satisfaction. It just took a long time and some back and forth phone calls. I thought they were...
I just returned from a 2300 mile road trip in my stock 52. It has 3.92 gears, and is able to cruise in the 55-62 mph range hour after hour. I've made four extended road trips with my truck in recent years--three to Pennsylvania and one to Kentucky.
Jim