My first build, I need some help please

Big difference between 450 and 550 hp.
450 is relatively easy, eddy heads and something like the cam you mentioned. But your gonna need to spin a 340 pretty high to hit 550 hp and depending on what you consider streetable, it will be a very racey motor.
You'll need heads putting out serious cfms, 300 plus, fairly high CR and a solid roller will help. If your shooting for 550 hp I'd go stroker to make it much more streetable.