carbuerator
Nitrous
Exhaust
Ported stock heads
No need to reinvent the wheel.....mustang guys have been making decent power like this for years.
a 4cyl to v8 swap is fairly straight forward but can get expensive quick. If I were doing this project I would search for a car thats already got a 5.0 in it. save yourself some time and the headaches of walking through junkyards or searching forums looking for parts.
steer clear of most mustang forums, most of them are filled with retards. Try to find someone local that has the knowledge you are looking for.
