15.0 mpg to 21.6 mpg!

With that combo, 13's is a sleep walk (providing you hook up).
I hope. And with pizza cutter 215's, the open diff has got to go. A TrueTrac is what I will go back with. Maybe $150 more than other posi type diff's, but I think it will be worth the premium. At this time, I think I'm going to stick with a 3.55 gear. That should put me about 4,800 - 4,900 rpm crossing the quarter mile line. Since it's not an interstate queen, I'll deal with it on the few occasions I take to the super slab.