To elaborate, he means Heads/Cam/Intake
A good intake (trickflow/edelbrock, even GT40) will wake the car up, match that with heads (AFR! ) and a decent cam, as well as a set of headers (good shorties, or long tubes, depending on your budget/application) and you will have one quick 5.0
With mustangs you have a LOT of options you just need to decide which route to go.. The roundabout way of building the car up one step at a time (taking it apart each time) or go all out and transform it into a beast..
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2003 Regal GS - the beater/daily driver - somewhat stock (yeah right). No its not a mustang, at least it's blown.
2001 GT Black on Black 5 speed
MM Strut Tower Brace/Weld-In Subframe Connectors/Koni Springs&Adjustables/Cobra Brakes/Cobra Rack/Tri-Ax/3.73s/SCT Tuner 56k miles