Ok, cheap mods. Standard 5.0 cheap mods that help: Gears as I mentioned will be a good mod. Doesn't add horsepower but puts your car in the power band quicker. Provides a "seat of the pants" improvement. A good tune up with Autolite #24s, an MSD cap with brass contacts, good 8mm wires. Advance the timing to 14-15 degrees and run premium fuel. Reduce timing if the car pings or rattles. Remove the air box silencer and add a K&N filter or go full CAI. An entire junkyard set of GT-P heads and explorer intake will add an honest 30 horsepower if you go that route. The problem is it would negate your headers. Tommy Vaughn Motorsports in Texas still ports stock mass air meters to match the rest of your intake track. Underdrive pulleys would add a little more. Delete your smog and bypass your A/C if you can live without both. Take weight out (numerous threads on the subject).
Cruising the misinformation superhighway in a Terminator.