Interceptor heads are E7TE's, just like a H.O. , whoever told you they were different is probably enthusiastically optimistic, unfortunetly, they are the same heads. But, as you know, there were several other genuine differences.
I hate to say this, because I always get slammed, but 3.55's are good for only 1 thing - Road Racing, they are the worst drag racing gear there is, it forces you to shift 4rth gear to close to the finish line and you go through way below your power peak, bad choice, stay with the 3.08's, they will allow you to go through in 3rd gear at your power peak, or get 3.73's.
Trust me, been there, done that!
