I know you can fit a 2v 4.6L without removing the shock towers. I think maybe some minor notching. I thought you could get a 4v 4.6L in there without going to an MII suspension ?
The new 5.0 is about the same dimensions as the 4v 4.6L.
Are you sure you have to completely remove the towers for the newer 5.0 ?
the coyote will fit into a 67-70 mustang without cutting the shock towers. however the fit is quite tight. you can slim down the shock towers though to get the room you need for headers.
that said, the best way to go is to cut out the shock towers and go with an aftermarket front suspension complete with rack and pinion steering.