OK, after doing a flight with the C-130, and flying it up to it’s maximum absolute Altitude here are the results!
The C-130 handled beautifully past it’s certified altitude, about FL330. The plane had no issues climbing. I was concerned about the speed, it kept dropping but the Mach stayed the same.
The C-130 was at full throttle the whole time, with about 1000-2500fpm, heading 250 out of KDEN RWY25.
FL350 - speed starts to drop
FL380 - Nose starts to pitch up a little
FL400 - Nose pitches up a little more
FL420 - Starting to get shaky
FL452 - Plane looses speed and starts to Stall
Next Test: GA Maximum Altitudes poll
Thanks IFC for your input! I enjoy gathering info then using it in IF!