I drained down my radiatior on my 454 and pulled the bypass hose and top radiator hose to replace the clamps along with replacing a water plug in the intake manifold.
I refilled the radiator without cranking the car. Should I have cranked the car, let it come to temperature, then refilled it with the car running or do you think I should be ok with no air bubbles in the system ?
Thanks.

You are correct to fill the radiator. Now that it is full, you should start the car and let it run and continue to top it off as needed. As the thermostat opens you will probably need to keep topping it off. Eventually you will have exchanged the air with fluid. Check the fluid level again the next time you drive it (do not open it when hot and pressurized).

Topping off the radiator will cause it to overflow when it hot soaks after shutting down. Fill it to the proper level, leaving an air space above the coolant.

If you drill a few 1/8 inch holes in the t-stat it will be much easer to fill up, much less traped air in the block.