Well, I didn't want a too big of a drop from direct to OD. With my 3.55 gear, standard 4 speed, 275R60 tires I run 70@3000. With the .81 I'm at 70@2400. With the .68 I'd be 70@2000. My engine has a nice rumble at 2400-2600 on the highway & I prefer to keep it.
