OK what I was running is a 06 F-350 with all the mods & studded on here except the intake and running the stock air. The truck has 325/20 s Vivian tunes lonney and wild which I was running.All stock injectors and turbo.Tuner is the SCT 5015 TS set on wild.Now this truck rocks but it seems to top out and hit a dead speed at about a 1/2 mile thats when the 6.4 running HS tune caught me and he caught me fast.My speed limiter is off just wondering if anybody had this issue its like it hit a top speed and would not go any faster.I took him off the line and to the 1/4 no problem by about 6-8 truck lenghts.It was at about the little better than 1/2 mile mark he really gained.He says he is deleted and performance tune and running 17 stock tires from a 06.Neither of us launched in 4x4 ,My 20 in are 2g worth of brand new and thats the first time they were spun not that would make a difference.I know I can beat them in a 1/4 but after that I need more any thoughts.The ported intake is high on the list but what about turbo size,air, and maybe injectors?? This truck is a daily driver and also a Bring It on Kinda thing with me.Have 3.73 in it maybe thats the issue?