+.040in. Dome Top Pistons with 9.6:1 Compression Ratio. Fits Big Twin 1984-1999 with Evo Engine. - Keith Black Pistons Fuel Paks/Tuners & ECM's # BC-53-1986 (3/8″ ID Hose)

# BC-53-1986 (3/8″ ID Hose) & # NMZ-NHC-B206 (Hose Clamps)

* S&S Crankcase # SS31-0052 directly replaces H-D # 34473-85A

* Significant improvements in performance

040″ Head Gaskets &

* Aggressive sport styling

+.040in. Dome Top Pistons with 9.6:1 Compression Ratio. Fits Big Twin 1984-1999 with Evo Engine. - Keith Black Pistons Fuel Paks/Tuners & ECM's # BC-53-1986 (3/8″ ID Hose)Features & Benefits: * Bore = 3. 538 * Stroke = 4. 250 * Hypereutectic Alloy is a cast 16% silicon content material. * Perfect for air cooled engines. * Low thermal expansion rate = tighter piston to cylinder clearance. * Complete kit includes: two pistons, rings, wrist pins and clips. Tech Tips: * 9. 6: 1 Compression Ratio with 80cc Head Chamber Volume. * Follow Ring End Gap & Piston to Cylinder Clearances as per the supplied Manufacturers