Pcm and engine swap
 

So few weeks back i blew up the motor in my 99 silverado 5.3 i find another motor only its a 4.8 from a 2002 silverado. the truck isnt all the way together yet but it is running but with my computer from the 99. So is this going to help or hurt this engine with the computer that is setup to run a 5.3? or just run it?

Truck running like ****
 

So I got my truck running it's throwing code p0405 for egr. Which is not present due to the newer engine so can I just plug egr valve back in and just zip strip it out of the way and run it or do I need to install the pcm for the 4.8 and do a relearn PLEASE HELP