Big difference i think here guys, you are all talking about manual boxes taking the punishment with dyno's etc, but isn't the topic about a gearbox for drag racing with around 500+rwkw. Even a car that can make 600rwkw on the rollers, prob won't last long flat shifting on the drag strip at those power levels, but an auto powerglide built correctly could and for a margin of the cost... So an auto may be the cheapest and best way to go if you just want times etc like try09's etc.
I personally would use an auto, along the lines of jatco 3 speed or powerglide. Powerglide if you want a reliable proven combination.
Cheers.