Cometic, builders cylinder base gasket set. 3-1/2″ copper

3-1/2″ standard bore. With ‘type A’ style gaskets. Includes two of each in .005″, .010″, .015″ and .020″ thickness. These are specialty copper base gaskets for mechanics that want to achieve a specific compression ratio. Type A gasket explained: Type A’ gasket is the early type introduced on the 1984 Evolution Big Twin models, and can be used on all of the 84-99 Evo Big Twin models and will follow the contoures of the cylinder base perfectly. They will fit 86-22 Evo XL, but stick out at the cylinder base. Both type ‘A’ and type ‘B’ have identical inner bore diameter, oil hole and stud hole locations. Gaskets for front & rear cylinder are identical. Only difference between the ‘A’ & ‘B’ gaskets is the outside perimeter.