Living with 3.91's

What it comes down to is personal prefference. Some guys don't seem to mind buzzing their engine at 3600-3800 rpm all day and others (like me) don't like abusing the engine like that. My Cuda had 4:10's in it with 27" tires when I got it. At 65 mph it was turning 3700 rpm. That'll wear on an engine fast. I rebuild another center and installed 3:73 gears. Much better!! Now at 65 it's only 3100 rpm so driving down the hwy is much more pleasant. Still runs good too. Probably lost a little out of the hole but it was worth it.