I know theres benefits of computer tuning, but I dont see how it makes you gain HP and TQ. Anyone care to explain?

 

fine tuning an engine makes the most out of what is there, you are *hopefully* increasing efficiency by setting the timing, and A/F ratio throughout the powerband, while the stock tuning were simply ballpark guesses by the manufacturer...close, but not perfect.

 

Stock LT1 owners can expect 15, sometimes as much as 20 HP gain from custom programming. This is either because the factory wanted to make sure people like me had a job :-) or because they were conservative in their timing curves and fuel mixture. Stock engines run too rich at WOT, and can usually benefit from more spark advance, especially in the upper RPM range.