Gears would be the cheapest option I think. 3.42's offer decent grunt with freeway cruising. I imagine you're running a 28" tire? Check out
WALLACERACINGCALCULATORS.COM
they have all types of calculators to help you figure rpm/mph with gear ratios and all.
Not sure what the Van had for Tires and Wheels when new...it had 15 inch Tires and Wheels on it when I got it, and they were old GM 3 piece Split Rims, so, maybe they were the originals.
They looked ridiculously too small to me, so I gave them the Heave-Ho and put on the 7:50-17s Rims and Tires, which look 'right'.
So, I am running 7:50-17 8 Ply Truck Tires, and ( being still close to new,) they are about 34 inches tall.
