Safe RPM for a 408" Magnum?

Thank you for all the input guys. Lots of good stuff to think about. The shift point issue when going from first to second was really right on the fence with regard to the stock rev-limiter. I'm pretty confident that the shift point was just so close to the 6100 rpm limit, that around 50 to 100 more rpm will result in consistent shifts into second without hitting the now higher rev-limit. I'll need to do a bit more testing to see if the issue is resolved though. If not, I will definitely be adding weight to the governor.

The car very rarely sees full throttle launches through the gears at max rpm's. It is a street rod after all, though so it does happen on occasion. :blob:

If this was a dedicated track car or even a regular visitor to that rpm range, I would have had more cam in it to begin with and went with a forged bottom end. It is a street car 99.99% of the time and I don't abuse it, but it does need to perform when I mash the loud pedal. It's a small block after all. If it can't handle rev'ing to 6500rpm when needed, something's wrong with it. Heck, I spin my 493 inch Mopar to 6500 rpm regularly.