When motorcycle drag racer T.C. Christenson and co-builder/designer John Gregory took their double-engined Norton Top Fuel drag bike to the top of the pro drag racing charts in the 1970s, Norton was known more for a heritage of TT wins and building great road bikes than running the strip.

Thanks to their brute force torque, Harley-Davidsons had dominated the top of the drag racing scene for years, but the Christenson/Gregory Norton’s ability to beat them earned it the name “Hogslayer.” Wisconsin video producer James Cutting, who directed and wrote the documentary Hogslayer, The Unapproachable Legend, emphasizes that bit of Norton’s biography to help underscore how stunning Christenson’s four Top Fuel World Championships — 1972 to 1975 — were.

Norton was no stranger to the race track, having won the first Isle of Man TT twin cylinder class back in 1907 and innumerable road races since. But Norton had never been much of a force in drag racing. That all changed when Gregory and Christenson began campaigning their 1,680cc fuel-injected Norton fitted with Gregory’s custom-made 2-speed transmission and slipper clutch, which gave Christenson the ability to make flawless launches. After beating up on the likes of Boris Murray and his twin-engined Triumphs and Elmer Trett and his Harleys, the twin-engined Norton even outran Russ Collins’ monster Honda, despite its trio of 4-cylinder engines.

Gregory was a Norton motorcycle dealer and brought the brand, his impressive mechanical skills and meticulous attention to detail to the team. Tom “T.C.” Christenson brought a tough, wiry frame, steely nerves and switchblade reflexes to the riding chores — as well as a rowdy sense of fun that was essential to keep the gravity of what they were doing from sinking in.