Deuce is spot on.
Get a 94-95 with the 5.0 or get a Fox body for the 5.0 option.
As for the 4.6 -
"The '96-'98 4.6Ls produce the least amount of horsepower of any late model V-8 Mustang." - How much horsepower did the '93 GT compared to the '96?
The only
real difference is the aftermarket, not the factory horsepower.