This is a GN1Performance "PORTED HEADS AND INTAKE COMBO" for a 1986 or 1987 Buick Grand National, T Type, Turbo T, or GNX 3.8 liter turbo V6. The heads feature a 177.5 stainless valves and exhaust are 150. They have new keepers, retainers, and new springs for a hydraulic cam, topped off with a 3 angle valve job. As for the intake manifold it is also fully ported to fit a Felpro 1200. Both items are poly coated throughout for a smoother flow. Heads or intake are available separately.                                                                                                              *Note- Sold on Exchange only.