With the average top-running Pro Stock (3.0) truck making roughly 1,100 to 1,200+ hp (at the crank), the axles of old are becoming a serious weak link. Case in point, Ryan Whalen, driver of the Cumminzed Out truck that's been in the magazine in the past, trashed his rear Rockwell 106's ring and pinion over the weekend, which in turn took out the front, upgraded Dana 60. Well, he reached his breaking point, and now an SQHD will be replacing the Rockwell 106 in back, and a 106 will replace the Dana 60 up front.
He's not the only one to do this. Rod Tarr, who drives the Super Ram Dodge (usually the truck to beat in the ITPA class) went to an SQHD rear, 106 front a while ago due to his setup calling for the change. A bunch of other trucks have also made the same axle changes due to the bar for more horsepower constantly being set higher and higher—and the need to maintain durability.
In years past, a front Dana 60/rear Dana 80 combo was enough for the 3.0 Class, but those days are long gone, as are the days of sub-1,000 hp engine combinations. Hopefully all of the axle upgrades will help maintain the class's reputation for powerful, yet reliable trucks pulling every other night of the week.