3.91 good or bad

I have 3:55's in my 340/ 4 spd/275/60/15 and 3:91 in my 440/auto/255/60/15 car. My favorite gear of all time is definitely the 3:55, the lower gears I've tried on the street were fun for a while but not something I would do again.

3:55 is probably your best bet for street cruising, light highway.