Looking to add some power to my car it currently houses a 4.6l and I was wondering what bigger engines with fit, I obviously already know the 5.0l will fit but I was curious about what else with more power will fit?

 

If I was you, I'd look for a Lincoln mark 8. As they have the 4 cam 4.6 and the mark 8 is essentially a T-bird or cougar.
If you get lucky enough to get a 96 to 02 cobra 4cam 4.6 which is basically same as mark 8. Of tp shelf would be a 03 04 cobra supercharged 4.6.
I myself had a sweet 95 with a stock 4.6 that I blew up the 4.6 while drifting and stuck a 97 cobra 4.6 in. It was a cake swap though I always wanted a 03 04 cobra supercharged 4.6.
I really wanted to do a Lincoln navigator 5.4 4cam up to I think 02 and either make a cobra supercharger fit or Whipple charge it.
After having many of nice handling vehicles, the T-bird platform from 89 to 97 are hands down my favorite car to auto cross and drift as they are very easy to modify and cheap to build! The mark 8s up till I think 98 are cheap to buy in decent condition. Oh my 95 bird passed all emissions too! If you go with the Mustang stuff... try to get 99 up as the same with the Lincoln navigator 4 cam 5.4 as the have better heads. I have a nice 96 4.6 mustang gt engine in a wrecked car now that I used the 5lug stuff for a 86 fox build I'm doing.