Alpha Performance Engines (A.P.E.) is an Australian builder of custom Harley-Davidson performance engines and bolt-on big bore kits, based in Gladstone, Queensland. For more than 15 years we’ve specialised in pulling serious, reliable horsepower and torque out of Milwaukee-Eight (M8), Twin Cam and Evolution engines — power that’s proven on the dyno and on the track, not just on paper.

We’re riders first, and that shapes everything we build. From the start, our goal has been simple: give Harley-Davidson owners cost-effective ways to get the most out of their engine. We don’t believe in a one-size-fits-all approach. Every combination is matched to how you ride and what you want to spend, so you get the right kit — not just the biggest one.

Our range runs from complete bolt-on kits through to fully custom, ground-up engine builds. That includes big bore kits taking 114ci and 117ci M8 engines to 128ci and beyond, performance camshafts, cylinders, forged pistons, engine covers and the supporting components to do the job properly. Every combination is dyno-tested and engineered for smooth, broad power that’s friendly on the valve train and happy on pump fuel — so your Harley is faster and still a pleasure to ride every day.

Whether you’re chasing more grunt for a Breakout, Road Glide, Street Glide, Low Rider S or Fat Bob, or building a dedicated strip or track bike, we work closely with you to deliver a result that suits your style, your performance goals and your budget. Classic street character or full race attitude — we build both.

When you choose A.P.E., you’re choosing Australian-designed and Australian-built performance, backed by genuine engine-building experience and a warranty tailored specifically to Harley-Davidsons modified with our products. We ship Australia-wide, with installation and dyno tuning available through our trusted workshop partners.

Unleash power with Alpha Performance Engines — custom Harley-Davidson engines and performance, built for the way you ride.