The orginal poster wants info on fenderwell headers. Why try to change his mind instead of answering his question? Fenderwell headers were all that were available in 1975 when I installed mine. Personally, I wasn't trying to copy a gasser. If one prefers TTI and Dougs that is fantastic, but I still say you can't beat access and convenience with fenderwells, plus the bends in the pipes are not as severe which may or may not increase performance potential.
