Doug's Headers D103-B Full Length Header 1-3/4″, 68-79 Javelin

Doug's Headers D103-B is a full-length, 4-tube header with 1-3/4 inch primary tubes built for AMC Javelin and AMX V8s, finished in Hi-Temp Black coating with a 3-port, SAP-shape collector.

Construction

Each tube is mandrel bent on a CNC machine for a consistent, accurate fit, and the flanges are machined from 3/8-inch stock so they resist warping under heat cycles. The tubing itself is 16-gauge, heavier than many stamped replacement manifolds, and the tubes are pre-polished before the Hi-Temp Black finish goes on. The collector uses a dog-leg exhaust port design matched to this application.

Fitment and emissions note

This header spans AMC's Javelin and AMX V8 lineup, listed across the 290, 304, 343, 360 and 390 through 401 cubic-inch engines built between 1969 and 1979; check your own engine and model year against that range before ordering, since the port shape and collector are specific to this application. It does not include provision for A/C-equipped cars. It is built for off-highway use only, and that restriction is tighter in California and in states that have adopted California's emission rules, so confirm your local requirements first if the car sees street use.

Who it suits

This is a header for a Javelin or AMX owner replacing a restrictive stock manifold with a full-length design meant to cut backpressure and open up the exhaust's flow through the midrange and top end.