getting it to breathe is your first goal.
a cold air intake, and full exhaust will do you ALOT.
A REAL cold air intake, a K&N FIPK is not a cold air intake.
then its on to the little things. but in my experence with ford 302's after intake and exhaust, almost everything else is a tiny difference (well on the mustang i felt a good jump after i did underdrive pullies, and a new intake manifold, but i dont think the manafolds on these trucks are that bad.)
The 302 truck intakes are great. IMO underdrive pullies don't belong on a truck.
after that, any good power is ALL about the HEADS!!!
cheap and easy would be a rebuild set of gt40p heads. prob gain a good 30-40hp
then a cam, thats about 10-15
with heads, cam, intake, exhaust, and all the other supporting mod's (bigger maf, bigger injectors, bigger throttle body, tune) youd be knocking on 300hp.
(well, with mustang 5.0's)
Definitely not 300hp. Maybe mid 200's, but these motors are only 180hp stock, and HP doesn't mean anything in these trucks, it's torque you're looking for. Most of these EFI trucks aren't mass air, and adding a bigger mass air sensor doesn't do anything unless the MAF itself is a big restriction. Stock 19lb/hr injectors are good for like 300-350HP. Aftermarket throttle bodies aren't really necessary until you get into the substantially bigger displacement motors.
hope this gives you a few ideas