Folks
Can anyone tell me about 5-speed g/boxes. In particular a datrally 5sp, with 5th gear= 1:1. What does this mean? Will this make my ute
a) stop roaring at over 90km's/ hr
b) make it even more fuel efficient
c)affect anything else in any other way

I am running a standard A12 which, despite being a little tired goes pretty damn good (it's original!)

Any info you have would be most appreciated. N.B - Is a tailshaft/ diff centre conversion required to complete the processes?

SpeedQueen