I have a 1991 honda civic si hatchback with a zc engine in it. I bought it with the engine already in it, without even knowing, anyways i dont think im getting the full amount of power out of it. When im in gear and i give it some gas it will accelerate but even if i open the throttle all the way i get more noise but dont go anywhere. I have DC headers and i have stock exhaust pipe from the cat. could this be the problem, i have no idea.

hopefull this much info will help :/