John Lingenfelter and Accel engineers have spent hundreds of hours at the flow bench and the dyno to ensure that their manifold base and runner designs outperform any other existing design. Precision cast and machined for port shape consistency and easy bolt-on installation. Runners equipped with cold start valve plug kit for 1989-91 applications and manifold base includes EGR ports. Runners bolt to stock or aftermarket base and base bolts to stock or aftermarket runners.