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

POKE 26999,173 
Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 27253,173 
Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 29690,173