With basic bolt on's I think they're gonna be about the same. If you're planning on swapping H/C/I, the 5.0 will probably be your best bet. It's a lot easier to work on than the 4.6 and you'll get a little better performance from it(more torque). I did see something one time that it costs about the same to get 300RWHP from both cars tho(H/C/I).