according to the attached file (which is from a link someone posted a while back), the SRT6 is rated at 330hp @ 6100 rpm ... and the max engine speed is electronically limited at 6400 rpm

I'm not sure that I've ever seen it hit an indicated 6400 rpm though, although I don't pay too much attention to it since I don't shift.

I thought InMotion had said they were willing to raise the rev limiter to 6300 rpm, which I've seen in a couple data logs is about what it tops out at with my InMotion tune.