Im having the idea that changing tire size gives the same effect then changin gear ratio,what rim size with what tire size would give the best result for drag racing in 1/8 mile?and to what gear ratio would that size be compared to?

 

The factory GT tire is probably 27" tall and uses 3.31 gears. If you were to run a tire smaller in diameter, that would be similar to the running a higher numerically rear gear ratio. If my math is correct, you'd get a little bit of benefit. Essentially, going from a 27" to a 25" tall tire would be similar to going from 3.31 to 3.55 gears.

The 1/8 mile is relatively short, and you'll need as much off the line acceleration as you can get. If the car is going to be used primarily for drag racing, and not much cruising, I would run 4.56 gears. However, if you still are going to drive it on the street and drag race, I would run 4.10 gears.