Engine swap or not

[91LX2Bfast]

Main difference is the 4.6 is a overhead cam engine where the 5.0 is the older overhead valve style with the cam in the at the bottom of the "V" above the crank.
There are stroker kits available for the 4.6L, but they are very expensive and really aren't worth it IMO.
There are cams available. Like I said above, the cheapest are regrinds, and they work very well. One guy over at stangnet just passed 300rwhp with his N/A 4.6 2v on mostly factory parts (ported PI heads, Bullitt intake, etc.) He gained a dyno verified 15HP with his $300 cam regrinds.
As far as going 10's. Well, Just ask Turbo99GT. He just went high 10's without even opening up the engine, and I am sure his car is smooth as a kitten on the street if he can keep his foot out of it.