This sounds familiar to me with some of the Challengers my dad has had. I don't remember the exact year, but I want to say he had a 2013 5.7 and he now has a 2016 (I think, maybe newer) 6.4 Scat Pak. Both manuals, but I think they both hit the top end of first way too fast to be useful. You didn't even get time to see a shift light and I'm not sure the traction control could tame it in time. Maybe different if you had really sticky tires that could load it up harder though.