The C-26 Dual-Quad manifold 350-5426 is designed for Chevy V8s with 1996 and later Vortec (L31) cast iron or the Edelbrock E-Tec aluminum heads. An external water bypass boss is machined into the front of the water crossover for use on 1996 and later Vortec, E-Tec and Fast Burn heads, this dual-quad is low profile for hood clearance on most vehicles. Air-conditioning bosses and front oil filler tube boss included. Stock alternator brackets do not fit. Carb center to carb center: 6-7/16'. Use with Performer-Plus cam 350-2103 for low-end torque or Torker-Plus cam/kit 350-5002 for top-end power.