Not so sure if any drag racers are running them but I know some circle track guys do and love them!!! Some of the fx machines and the super mod/outlaw twins with verticak shaft motors are using them with great sucess and those big nasty twins make upwards of 80 plus horse!! You will be fine with it. They are really pretty simple. Its a cast iron box, has an input and output shaft with bevel gears inside. Add oil and abuse it!!! They are stout!! Some are 1:1, some 2:1 it just depends. But on another note, if you are dead set on using a transmission, ya might look into a 400. They are basically a 600 transaxle center section and are also very strong. I have a friend with a healthy kohler bp tractor and said he raced it for 2 seasons before he decided toi change the oil and everything inside looked great!! Hope this helps