My 455 Buick shifted past 6000rpm on hundreds of passes at the track although it wasn’t stock. TRW Pistons, stock polished rods, oiling mods, main studs, light weight valves and springs, balancing, etc. 6.85 in the 1/8th NA. Many passes with 250hp nitrous. Many more with 175hp. I had several friends with 455 Olds engines at about 5800rpm max. I’ve never seen the issues or fears decribed on this site with properly set up Buicks or Olds big blocks. Maybe it was the lack of ‘give a s**t that we had. My Caddy engine will be put through the same ‘abuse’. All of these cars had thousands of street miles on them. Balance that 350 with proper clearances and don’t cheap out on the springs, locks, and retainers.