This is my point exactly. I picked up 130hp, give or take, from merely hollowing my cats, adding a cam and replacing my airlid. Total cost, $1020, and you can hang with blown 4.6 2v's HP wise. Displacement? It's a valid argument. But why doesn't Ford put the 5.4 N/A in a Mustang? I would assume it's because of fuel economy reasons. We all know that mod for mod in the N/A world the LS1 responds hands down better. Why is it people are so quick to pull the displacement issue? Chew on this. If increasing the displacement on the 4.6 to 5.4 does so much, why is the new Chevy Silverado's 5.3 rated at 315hp and the Ford is 320 in the Flex Fuel and 310 in the std. model? The 4.63v is rated at 292hp. Not much of an improvement to me. These are both '09 MY vehicles, apples to apples. More eye catching, the jump from 4.6 to 5.4 netted 18hp. The answer is simple. The 4.6/5.4's are limited by head design. There is just too much real estate taken up by the OHC technology to create a free flowing head, hence the 2,3 and 4v versions. This is why charging a modular is a Must for any kind of power. Now, i'm well aware that there are extremely good examples out there to prove me wrong, but I don't think you'll find a Cam(s), CAI, catless N/A 4.6 or 5.4 producing 480HP. Put cams, hollow cats and CAI on a Mustang, you might get 50hp fly. You seem to be well educated on the LS1, so you should also know that the reason the gain is so big with a cam is that they have such a small cam factory they don't even have an EGR valve ('01-'02), this could also attribute to the 25+MPG, even with the larger displacement. Add a cam to the charged LS1 and I think the numbers would be very, very different. I was pounding out a [email protected] getting 28MPG going to the track, and could bury the 155 MPH speedo with the 2.73's, all with only a Lid, Tune, no cats and cutout. I guess what i'm trying to convey is, I want to see an example of a Mustang, running [email protected] or better, at a corrected altitude of 1500ft. Only allowable mods are CAI, Gutted Cats, a computer tune and cutout lid. It has to be an Auto and have 2.73's. This is the basis of my argument and holds true to the OP's topic. And, is the whole reason I switched to the dark side, cheaper, faster N/A HP.