On the other hand another question I need answered would be, what is the correct or shall I say right size headers I should use with my engine to get the best performance? Thanks again !!!
TTI has only one size header for you. 1-5/8 to 1-3/4 with a 3 inch collector. HP dependent, exhaust pipe size comes into play, but, if your engine is a basic healthy engine, 2-1/2 will handle it fine. Once you get to the hi400 level, depending on who you want the car set up, street or track, the pipe may change to 3 inchs for the track.