They will go that high. I was at 340 on mine, but it took a **** ton of work.
I think (THINK) I could get close to 400 out of them, but by the time you did all the work you might as well try and find some W7’s because that’s what you’d have.
Numbers, as well all know, are relative.
Mine went 300 on a reputable bench, and the car at 3220 has been 140 mph on leaf springs.
I don’t know of many that run much if any better no matter the dyno numbers