ok, ill give my two cents but ill need them back cause i gotta buy gas.
1- I say stock its 300hp
2- single digits, gonna need a lot of fuel to get 550 hp.
3- my supercharged 5.3 made 400hp lasted 170k until the truck got wrecked.
4- id say yes
5- how deep is your pockets 550hp is a big ask on na
6- lots of 5.3's on marketplace for $450- to $1200 around me
7- clean heads and covers are nice, dont buy a rusted hunk of junk.
8- Id doubt you could get 350hp out of those upgrades.
Best hp per dollar for a 5.3's is to add a turbo. why reinvent the wheel turn up the boost to your wanted power level, blow up and repeat.
https://sites.google.com/site/sloppy...unkyardturbols