26. Stillen had to perform a bit of tuning to the truck (adjusting fuel, spark, and timing) so it would accept its new exhaling apparatus and we were rewarded with a healthy jump in performance. How much? How about an extra 41.17 hp and 30.71 lb-ft? Our new numbers on the dyno had us at 415.35 hp and 397.07 lb-ft, with increases from the bottom all the way to the top.