Gryphon

Which stock prop are you talking about?

The Prop for the P-51 can not be used, because that P-51 has a gear reducation so it can swing a large prop slowly. You can not swing a 10X8 prop in a direct drive configuration using a 480 motor.

Your plane comes with a 5.9X3 prop (I believe) same as the original stryker, same as the larger one of the two that comes with the F-27B intended for the non Li-poly setup.

Since the strykers come with the same motor and prop as you, and they also do recommend a 8 cell for better performance. You should feel very comfortable using your original prop with the 8 cell battery.

I have dozens of full throttle flights on my stryker with an original 480 motor and 5.9X3 stock prop using 8 cells.

If I were you I would also try using the F-27B li-poly prop 5.3X3.3. I put it on my setup using the 8cell nimh battery and my plane flew faster with this prop. I was expecting a reduction in my climbing power, but I was not able to notice any.

2.3mm Prop adapter and an APC 6X4 will bump up the power consumption, but will increase the performance of your plane, should be the most fun setup. I know the ESC/Receiver unit of the stryker can handle this prop on 8cell or even full throttle on 3 cell Li-poly (11.1V).
A motor Heat sink is well worth it for the 3 cell LI-poly if you plan on flying full throttle till the battery runs out. Do not bench test full throttle non-stop in your room due to lack of airflow around the motor (I learned the hard way).

******** I do not know what ESC your plane comes with, but I have no doubt that you would be o.k. with some throttle management using the big APC 6X4*******

Have fun