If you're using the original 88-2000 front clip that had the vortec 350 they will fit. From the cab back it doesn't matter because the headers will direct the exhaust pipe on top of the transmission crossmember on each side of the tranny. I will have a disclaimer with the headers that says what engine adapter thickness, engine angle, engine positioning to frame and everything to make sure the headers will fit your application so you don't waste your money on them.