This is the first time I have dynoed my truck since I swapped to the LS1/T56. The only internal mods is an 02 LS6 Cam. I have the usual external bolt on's with Nelson Tuning, I made 339.14 RWH @ 6100 and 332.64 RWT @ 4800. My rev limiter caught me at 6100 but it looks like it was going over the top on the graph but there might have been a couple more if the limiter hadn't shut things down. This was done on a Dynojet. I only made one pull and it was in 4th. I am sure I show a few more horses than an automatic since I don't have quite as much loss running through a manual trans.