MHP M8 135 Stroker Pistons 4.625" Stroke 4.313" Bore -2.5cc - MHP-P4313-135

Moonshine Horsepower M8 Stroker 135 Pistons for 4.625" Stroke

Built specifically for our high-performance Moonshine Horsepower Stroker 135 packages, these pistons are engineered to deliver reliable power and durability in Milwaukee-Eight engines. Whether you’re running stock H-D Screamin’ Eagle Stage IV heads or aftermarket heads, these are the pistons we trust in every MHP 135 stroker build.

Made from tough 2618 aluminum with a molybdenum (moly) skirt coating, they’re designed to handle serious heat, high RPM, and the demands of a stroker combination. We run these in our own engines because they hold up when you push the limits.

Key Features

• Forged 2618 aluminum construction with moly skirt coating for strength and reduced friction
• Optimized for the MHP Stroker 135 combination
• Clearanced for CP Carrillo rods
• Clearanced for plus 4mm oversized valves
• Designed to work with stock H-D Screamin’ Eagle Stage IV heads or aftermarket heads
• Matched to our MHP-spec Total Seal ring pack (Part # MHP-R4310A)

Technical Specifications

Ring Pack (Sold Separately)

MHP Spec’d Total Seal Ring Pack – Part # MHP-R4310A

• 0.9 mm Gas Ported Top Ring
• 0.9 mm Napier Second Ring
• 3.0 mm Oil Control Ring

Cylinder Fitment & Honing

These pistons are sized for a 4.313" bore. Stock Harley-Davidson 4.310" cylinders will require honing for proper clearance.

We perform the finish hone in-house on our CNC Rottler using a 12-stone head setup. This gives us precise control over final size, straightness, cross-hatch angle, and the peaks and valleys of the hone surface — critical for ring seal and long-term durability. We can also hone your existing 135 cylinders for use with these pistons. Please contact Nick Zinola or Jamie Lima for this service and pricing. Phone 615-274-4170

Why These Pistons

These aren’t off-the-shelf parts. They’re the same pistons we use in every Moonshine Horsepower Stroker 135 engine we build. The combination of 2618 aluminum, moly coating, proper clearances, and our matched Total Seal ring pack is intended to deliver consistent performance under real-world high-output conditions.

Ready for serious power. Contact us if you need cylinder honing or have questions about fitment in your M8 Stroker 135 build.