The 5-speed gears are narrower than the 4-speed gears, but can still handle a good amount of power, usually upwards of 850 HP/TQ at the crank in a typical sand car.
I will typically suggest gearing 5-speeds to use 4th gear as the top speed gear, and 5th gear is just the extra gear when needed or on the longer runs to keep the RPM's down.
5-speeds are better for lower powered engines for closer splits between shifts. Most sand cars will never need a 5th gear, therefor 4-speeds are more common. Most anyone with 600+ HP/TQ will only ever need a 4-speed in a true sand only car.
John@Outfront, you need to look into the new Gen 3 shift mechanism next time you service the trans. Speeds up the shift actuation to prevent rounding the dogs off, and allows for better clutch-less shifting. You should call me sometime about my thoughts why using the clutch can actually cause more wear on the dogs when driving hard.
