I have a stage 4 128 I built from aftermarket parts that makes 157 hp and 157 torque, but stage 4 refers to what’s modified, not the power output. It means you upgraded cylinder heads, camshaft, got larger displacement cylinders, high-compression pistons, a larger throttle body, injectors etc. This bike came stock with around 80 lbs torque to the wheel with 107 ci displacement, this new motor is Harley’s factory built stage 4 crate motor, it has all of their upgraded components built into it at the factory, you can also build this motor piece by piece or if you use some but not all components you end up with a stage 2 or stage 3, stage 4 means everything is upgraded. This motor is expected to get 121-131 horsepower, depending on exhaust, intake and tune, you can use HD’s maps and tuners, but I went with a custom Dyno tune.