i have taken the 3.1l out and replaced it with a carbed 350.i would like to put shortie style headers on or long tubes but my question is i know that the 3.1l exhaust won't bolt up to the v8 so how much modifiing will i have to do? will i need a crossover tube between the headers i plan on installing a flowmaster catback exaust with dual tips out back but from the crossover to the cat can i use the old exhaust its in great shape! ok! now you know my confusion can yall help me out with some advice? thanks