So I recently bought a truck with a Vortec 454

A couple things that have been done to the truck are the cats were removed and the EGR valve was blocked off. I have the cats, the PO gave them to me with the truck. Now, the truck has no tune on it, it’s running stock software. What I’m trying to decide is if I want to unblock the EGR valve (probably will) and re-install the cats (probably not).

So anyone familiar with tuning these engines, what should be my plan here? My internet research leads me to conflicting views and it’s hard to find anything authoritative on this. Should I leave things as they are and take it to a tuning shop? Should I just unblock the EGR valve and run stock software? Should I also reinstall the cats?

Thanks in advance