4dohs4mohoes

i put an ex motor in my 91 civic and hit some probs. it starts up fine and everything but when i start to drive i hit the rev limiter at like 3500 rpm. if i dont have the vtec hooked up....could that be why. and i also am using the intake mani. from the d15b2 (dual point thingy) could that be a reson too. please help....