Panhead Vs. Knucklehead Vs. Shovelhead: Harley-Davidson Engines, Compared

When talking about timeless Americana, it is difficult not to mention Harley-Davidson, the motorcycle manufacturer that has had the American streets in a tight grip for more than a century. In the many decades it has been around, the company has had a hand in setting some of the best trends in the motorcycle world, like building comfortable cruisers in the name of the Softail and fostering motorcycle clubs like the Hell’s Angels. However, among some of its more interesting achievements is building some of the most talked about engines over the years, three of which are the Panhead, Knucklehead, and Shovelhead. Compared, these engines all share the awesome Harley name. However, that’s where the similarities end, as they each have distinct characteristics and design features, such as different valve cover styles (which is where they actually get their names) and horsepower.
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Harley-Davidson officially began in 1903 with the Model 1, which used a 24.74 cubic-inch inlet-over-exhaust single-cylinder engine. Down the line, the company engineered the Panhead, Knucklehead, and Shovelhead, each of which would have ample time to shine before being retired. Interestingly, each engine succeeded the other, starting with the Knucklehead, then the Panhead, and finally, the Shovelhead. Let’s examine each of these to understand what they brought to the table, how they compared to each other, and why Harley saw fit to ultimately shelve them.