The "Doug" of "Doug's Headers" IS Doug Thorley. He had "Headers by Doug" in the '60s and through the mid '70s. A "divorce" happened, and "Doug Thorley" headers came next. They weren't very good, and the company folded. He "came back" about 10 years ago, making a higher level header. Good stuff, alright.
Four-tube headers outperform three-tube "across the board", provided the correct tubing diameters are chosen. Three-tube headers are strictly for bragging rights ("I have headers!"). The Ram Air and HO manufolds "make" more power than three-tube headers.
