Stroking the LS block is a drag racing motor tactic. It results in horrible rod/stroke ratios and a motor that wears out quickly.
It's a power play, and not something you want to do to a car that is expected to do regular street duty.
If you try to improve the ratios by adding a deck plate, raising piston pins to the max and using longer rods, etc, then you start to get into some costly mods that may not be what he wants.