Hi Thunderchild,
We need complete details of your circuit to determine a suitable darlington transistor and driver for it. The gain of your BDX53 is rated at only 3A. It isn't even rated at 8A but the curves show its gain dropping quickly above 3A.
How much saturation voltage can your load tolerate? At 3A, the BDX53 has a max saturation voltage of 2V with a base current of 12mA. Its saturation voltage will be much higher at 8A where it might need a base current of 140mA!
The max recommended supply and input voltages of the 74HCxx series is 6V, so might not be suitable for your circuit. :lol: