I have a 83 GT that i am currently playing with it has a stock 88 roller motor with god only knows how many miles a e 303 cam steath intake and a holley 750 vac 1.7 rockers and ported e7 heads stock 87 headers and matching stock cat h pipe with flows 3.73 and 5 speed i want headers and h pipe but dont know if long tubes are worth the extra money