Manifold Header for Nissan D21 Hardbody Pickup Truck (1990-1995) 2.4L 4WD 4X4High Flow Exhaust Manifold Header for 1990 1995 Nissan Pickup (KA24E D21) What it Does: Replaces the restrictive factory cast iron manifold with a mandrel bent tubular header to improve exhaust scavenging and reduce backpressure on the KA24E SOHC engine. The Stock Pickup Deficiency The OEM cast iron manifold on the Nissan D21 Hardbody is a significant bottleneck. Designed for low cost mass production, the factory 'log' style manifold forces exhaust