what efi parts are these and can i use them on my 360 magnum

I dont wanna sound like an expert, but my answers just get kinda right on because i dont wanna sit all night and type:-)
next is based on running haltech or MS. You dont want to run the stock ecu if you are serious about injection and more than a stocker hp.
50lb injectors last to rule of thumb x10 HP on a v8, so 500hp. guess some more depending on fuel pressure! idle is not a problem unless the injectors are crap. 50lb is usually no problem. BIG camshaft is bigger issue to tune tu run nice,but doable.

yeah, you may tune the haltec yourself with a wideband lambda, its like megasquirt and those. I have not tried MSD so, cant give you an answer on that one.