OP said as far as he knows the motor is a stock 383. I'd be first in line to see a 383 with a stock cam and valve springs 'hold' power to 7200 RPM. Not gonna happen. As far as valve float, you'll know it when it happens. It will sound like your motor is 'shooting ducks'. Basically, the RPM is too high for the valve springs to return the valves to the seats, so you get 'bouncing' and leakage into the intake and out the exhaust. Really tough on all the components in your valve train, but, thankfully, not your problem...
