410 LA small block will not rev past 6000

The dyno graph list peak hp as 416 hp @ 93.75 mph and best I can see tq is 455 @ that mph and peak tq is 475 tq @ 77.78 mph and hp looks to be about 360.

416 hp x 5252 / 455 = 4800 rpm
360 hp x 5252 / 475 = 3980 rpm

So 416 hp @ 4800 rpm and 475 tq @ 3980 rpm.

4800 hp peak is pretty low but it seem like it's a short peaky spike there for whatever reason, around the 100 mph point seems like a second hp peak broader more sustained at around 5200 rpms still way short of 6000 rpms.