2004 GMC Sierra 1500 5.3 w/ engine swap...ECU?

[Steve]

Bought it new in 2004 with the 5.3L V8. (285hp)
In 2008 the engine went bad after about 89,000 miles
Went to the dealer payed almost $6000 for a brand new engine from a 2008 5.3 (315hp)
Now my question is am i getting those extra 30 hp since the truck still has the same ecu from factory?
Or do i need to buy a new ecu from a 2008 5.3L? i saw some on ebay for a $100. but im not sure if i really need it.

 

[Molson02536]

Bought it new in 2004 with the 5.3L V8. (285hp)
In 2008 the engine went bad after about 89,000 miles
Went to the dealer payed almost $6000 for a brand new engine from a 2008 5.3 (315hp)
Now my question is am i getting those extra 30 hp since the truck still has the same ecu from factory?
Or do i need to buy a new ecu from a 2008 5.3L? i saw some on ebay for a $100. but im not sure if i really need it.

If the dealer did the install your should be good to go, the extra 30 was a update to the ECM to run the engine. I am sure the dealer must of or should have down loaded the updated program for the new engine.