Good 400+ HP 360 build

If you have fresh heads (even stockers) all you need is a camshaft to make 400hp. If they are stock they might need the guides and spring seats machined for the springs many cams need and you might need valve retainers and locks - but none of that's a big deal or really expensive.
Take an LA shortblock - stick some performance pistons in it to get the static compression up a little, then stick a cam at least as big as the XE268 in it. you don't have to worry about "0" deck unless you want to add closed chamber heads in the future. personally I'm not a fan of those "sound" cams - not Comp's or Hughes. Stick a cam of 230-240° @ .050 and your intake, a slightly bigger carb (750cfm) of any manufacturer, some cheapie headers and a good ignition it will reach 400hp. The adjustable valve train is not necessary with cams equal to or smaller than the XE268. The reason they want you to have adjustability is because the lifter preload on the higher rpm lifters is very precise. More precise than the factory stuff allows. If it was me I'd say just go with the XE268 and use the factory lifters and 901-16 springs. Then it's all drop in stuff. Lunati requires a dual spring for thier "268" cams. Hughes likes big spring pressures too.