They used SOME numbers that had the ratio in the number. If that was one of those, the last three would be the ratio, 3.26, but as you've already found out, it's a 4.56 gearset. That's a good gear. Run a 28" tall tire and it'll help cut the effective ratio a little.
Drag racing theory to which I prescribe: run the tallest tire that will fit on the car. Given a choice, taller is better than wider (depending on rear gear.)
