Component selection will determine RPM range. The 6500 RPM limit is just an old wives tale.
20 years ago I ran a 383 with 5.56 stock chevy rods and heavy TRW pistons. I wouldn't spin that one much over 6500.
Fast forward to today and I launch my 383 at 6400 and go through the traps at 8200.
The as-cast 210cc Pro Comps are not the greatest heads I've seen. They are kind of catch 22 head, for the price they are OK, but if you have to pay someone to do the port work required to make them really work you could have had a decent CNC'd head.
I run a set of 210 Pro Comps on my Moms 3100lb door car, 400ci that will run 10.40's in decent air. I put about 3 hours into each head making them respectable. My time is free for my Mom though.