+.040in. Dome Top Pistons with 8.3:1 Compression Ratio. Fits Big Twin 1978-1984 with 1340cc Shovel Engine. - Keith Black Pistons Handlebars 1" - Chrome * Includes Heat Shields

* Includes Heat Shields

For: H-D Dyna models

which increases rpm for more precise tracking

* The PowrFlo Intake system consists of an aluminum cover and all the fasteners

ThunderMax comes 100% assembled

+.040in. Dome Top Pistons with 8.3:1 Compression Ratio. Fits Big Twin 1978-1984 with 1340cc Shovel Engine. - Keith Black Pistons Handlebars 1" - Chrome * Includes Heat ShieldsFeatures & 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: * 8. 3: 1 Compression Ratio with 117cc Head Chamber Volume. * Follow Ring End Gap & Piston to Cylinder Clearances as per the supplied Manufacturers