GALLERY By Event | By Car Type First take a friendly piece of 6mm plate steel, and drill it out.Next, file away the bits that don't look like they should be there. Note exhaust stub tube inserted in port for correct angle when welding to manifold plate.Inlet manifold for S1 head, triple 1 3/4 SU's. Built by Terry Handley.Shown fitted to head.Next job is to make the exhaust headers which fit onto the stub tubes.