Harley-Davidson takes the Milwaukee-Eight Extreme Ported four-valve cylinder heads, and goes to work. The heads are CNC-ported, and the diameter of the valves is upped by a millimeter. Further, The Motor Company machines the combustion chambers to a shape that improves combustion efficiency.Feeding the top end is a 64mm throttle body and matching intake manifold. The fuel injectors are high-flow, moving 5.5 grams per second.A Harley-Davidson high-lift SE8-517 camshaft with a high-performance cam bearing keeps everything mechanically synchronized.While the intense power is a reward all its own, the Screamin’ Eagle 131 Crate Engine also has styling touches to make sure everyone knows your Softail is packing serious firepower. There is 131 Stage IV badging on each cylinder head, as well as the timing cover. Plus, there are two finishes—Black and Chrome, as well as Black and Gloss Black.If you have Harley-Davidson install the Screamin’ Eagle 131 Crate Engine in your new Softail, it gets the same 24-month manufacturer’s warranty as your motorcycle—you have a 60-day window to decide. When the motor is installed in a Harley-Davidson older than 60 days, the warranty is of the 12-month factory limited variety, and it must be installed by a dealer.We already know the Screamin’ Eagle 131 Crate Engine fits 2017-later Harley-Davidson Touring models, and not any Trike models. Softails are now part of the compatible package, though not all models. Harley-Davidson hasn’t revealed which Softails work with the 131 powerplant. Because the 131 motor uses the standard 114 stroke, we surmise that Softail 114s are immediately compatible. Check with your Harley-Davidson dealer for details.The oil-cooled Screamin’ Eagle Milwaukee-Eight 131 Crate Engine runs $6195, with the Twin-Cooled version’s price tag just $200 higher. Some older models will require clutch and oil pump upgrades at additional cost. Also, everyone gets to pay for an ECM recalibration via the Screamin’ Eagle Pro Street Tuner, if they want all the power to be unleashed.