gear ratio help!

solrac, ya need to Google a mph / gear calculator, and there are hundreds on the www

Depends on your rear tire size, and what you are willing to put up with for cruise RPM and mileage loss

I run 3.7x, and with my tires, 70 mph is about 3400. I don't drive this really long distances on the freeway, so for me it works out. My old 70 RR had 3.54 and it ran just exactly 3K at 70, and that little drop in RPM went a long ways