So you’ve upgraded your M8 engine to the highly sought after Screamin’ Eagle Stage 4 131 cubic inch engine package. It was great at first, however now you have gotten used to it and you are craving more! You’re not alone! We hear this time and time again! The pistons that come with the Stage IV kit are ok, however they are not GREAT!

These replacement pistons were designed specifically by Jim to be a direct replacement piston set for your crate or Harley built 131 engine. Simply pull your old pistons, dingle berry hone the cylinders and install the new pistons! These pistons in combination with Jim’s M835B camshaft and a good exhaust will have you making 150 torque and 150 horsepower in a Gen 1 engine and over 160 ponies in a Gen 2 engine! We’ve tested that exact combination with several exhaust systems and have gotten similar numbers across the board!

CP Carillo manufactures the pistons to Jim’s specs. They are then coated by Calico Coatings with the very same coating that goes onto every piston in a NASCAR engine! After coating, each piston set is personally inspected and packaged by Jim to ensure product consistency.

Piston kit comes complete with: Pistons / Ring Set / Wrist Pins / Wrist Pin Clips

Designed for the Harley Davidson Screamin’ Eagle 131 Stage 4 engine: 4.310” Bore & 4.500” Stroke

Jim recommends a .020” set of base gaskets and .030”-.040” set of head gaskets. Your head gasket thickness needs to be calculated based on your cam choice as well as your cylinder head final cc amount (Untouched Stage IV heads measure 94cc on average)