These are large oval port cylinder heads with open style 115cc combustion chambers and 300cc intake runners. In addition to the nearly 80lb weight savings these heads offer over factory cast iron heads, they will yield about a 40hp gain over stock GM 990 castings. In unported form these heads will support 500+ horsepower on pump gas. If you are looking for a race grade head that is comparable to Edelbrock, Dart, Trick Flow, Pro Comp, or AFR at a fraction of the price look no farther then these. These heads are cnc machined and assembled by us. These heads work great on Caruretor and fuel injection engines and no…