Questions about a 2006 5.7

The stock intakes flow much better than they’re given credit for. On my 6.4 project, with zero mods on the intake side it’s putting down 615HP to the crank.
Its just turning into a big black money hole right now. I will drop a few thousand into our camaro project that never ends but so far its pistons, heads, gaskets, turned into 4 rods, push rods now since pre eagle are too short, intake that I expected but not getting a 6.1 aluminum for 5-600, then the valve covers wont fit so tack that on just makes the project that should hopefully last into a build. Considering I bought the car with a "hemi tick" from a mechanic that most likely knew it was not the hemi lifter tick. After putting a couple grand into it, those used motors start to look like the better choice, but then again, what do you get or will you be dealing with rebuilding that one.