I changed my rear ratio from 5.14 to 4.10, and was planning to go to an NV 5-speed as well, for the overdrive. But, having driven the auld girl for a while now with the new ratio, I've decided that I won't need the O/D unless I was to start logging a lot of miles on Epic #2. She's completely driveable now, where before she was screaming at anywhere over about 40 - 45 mph. Now, I could cruise at 55 - 60 all day. And while I haven't gauged fuel economy yet, I know there's a BIG difference.
