are you going to pull the engine and have fresh rings and bearings and pistons (if necessary)installed? What about a fresh oil pump?
Hopping up a high mileage engine is a good way to get to the rebuild stage in a hurry. Right now you might be able to overhaul the short block without having to bore it oversized, Few engines like more then an .030 boring and many don't like that. Run it til it breaks and you will be replacing a block and a crank and possibly more. That is okay, 5.0's are plentiful and relatively cheap, just know what you are in for. Heck even a good (complete) gasket set these days will set you back nearly $200.00 bucks
Not to be a detractor her, you can do what you want, but it is far more economical in the long run to wait and do it all at once on a fresh engine.
With your mods in process you do need to update the timing chain.