My 4 speed is holding up just fine behind my r5 which is close to 900hp, but only around 570 ft lbs. But I am running a short tire as Cab mentioned 0nly 27" tall. Blazes the tires off the rims on the street in every gear. As for the track maybe I'll stick with radials instead of an all out slick. Working on my pinion angle right now so I can get to the track this weekend. Hopefully I can make a full pass