By replacing a factory 2-into-1 joint with a Dr. Gas merge Y-pipe collector will produce gains from 9-20 h.p. Many applications will only permit a single exhaust system, or an X-crossover will not fit. Dr. Gas makes a straight and curved 90 degree and special angle inlet angle Y-pipe merge pipes or collectors. The outlet works best when it is larger in size than the 2 inlets. A venturi cone transitions the diameter up, after the merge. Torque and horse-power improvements are nearly identical to the gains from an X-crossover. If the inlet branches from the header or manifold are equal in length the exhaust will have the same smooth higher pitch note that our x-crossovers have.