Unlimited lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 2392,50 
Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 2392,50
POKE 2847,99 
Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 4566,176