Description Adjustable IMCA headers feature a long primary stepped header, 1-5/8″ – 1-3/4″ S/B Chevy. 3″ collector. One 90° turnout and one 60° turnout. Adjustable length to allow for engine and/or foot box location, as well as power band tuning. TWO-PIECE ADJUSTABLE HEADERS – Headers have removable collectors and employ a “stepped” primary tube design for increased horsepower and torque. Adjustable feature means existing collectors may be replaced with different slip-over collectors to allow adjustment of engine location
