The Ford HO 5.0 is kind of a dog by today's standards where the new 5.0 Mustang motor makes 400HP.
Our old 5.0's can be modified to max out the factory computer and fuel system though. I did intake, exhaust, and went a bit further with gears.
Let the engine breathe easy with better intake and exhaust and you can max out what the computer can do with the stock 19lb fuel injectors. Taken a bit further there is the heads that pump air to the cylinders. There are Trick Flow intakes and heads that will make more power than the fuel system and computer supply without more programming or bigger injectors.
I went with a Mustang Cobra intake and kept my E7 heads and new exhaust for nice pick up in performance. I also did a rear end gear reduction which can be a straight trade of performance for fuel economy. 3.08 rear end to 3.73 was a 21% gear reduction and similar loss in highway fuel economy. It makes the old car impatient for old men and ladies in your way around town though. Rather than quietly waiting and cruising until the old folks get out of the way.
1992 Tbird LX 5.0, 3.73 gears, 1995 Cobra intake, deleted air silencer, 2.5" mandrel bent dual exhaust, SCP shorty headers. Updated four-hole fuel injectors. SK shift kit in AOD. Vogtland 0.9" springs, Tokico and Bilstein shocks.