E.J. Potter: Putting a Chevrolet V8 Where a Motorcycle Engine Belonged
The Michigan Madman Had a Tape Measure and Very Few Reservations
E.J. Potter was sixteen when he started thinking about putting a Chevrolet V8 into a motorcycle. Most sixteen-year-olds confronted with that idea would have benefited from an adult explaining why Chevrolet had never offered the option.
Potter reached for a tape measure.
He measured a Chevrolet small-block, then measured a Harley-Davidson engine. The Chevy was longer, naturally, but its height and width were not as hopelessly different as common sense might have preferred.
That settled it.
Potter found an old Harley frame, a junkyard Chevrolet 283 and began cutting. By 1960 he had produced a motorcycle with eight cylinders, several hundred pounds of engine and very little concern for what the motorcycle industry had been doing up to that point.
The manufacturers had spent decades overlooking the V8 motorcycle.
E.J. corrected the oversight.
The First One Was Bloody Mary
The original machine was wonderfully crude. A mostly stock Harley frame carried the Chevrolet engine, a Whizzer fuel tank sat above it, and a homemade intake squeezed carburetors into whatever room remained.
There was no radiator, little electrical equipment and no conventional transmission. A chain connected the engine to a homemade clutch arrangement, and another chain carried power to the rear wheel.
Calling the result a motorcycle built around a Chevrolet engine gives the motorcycle half too much credit.
Potter had attached enough motorcycle to a 283 to provide handlebars, two wheels and a general suggestion about which direction the Chevrolet ought to travel.
Starting It Was Easier Than Launching It
A small-block Chevrolet produces more torque than a motorcycle clutch from 1960 had any reason to expect. Potter needed a way to get the engine running hard without asking the drivetrain to absorb the entire argument at once.
His solution eventually became part of the act.
The rear of the motorcycle sat on a stand with the tire clear of the pavement. Potter fired the V8, brought the engine into the useful part of the rpm range and let the rear tire spin while the bike itself remained stationary.
Then he dropped it off the stand.
The spinning tire hit the pavement and tried to find traction.
Usually it failed.
Failure, in this particular case, was the safety system.
The Rear Tire Became the Clutch
If the slick had hooked immediately, several hundred pounds of Chevrolet engine might have continued forward while the remaining motorcycle reconsidered the arrangement. Potter used wheelspin to soften the hit instead.
The rear tire smoked for an astonishing distance while the motorcycle gathered speed. As road speed finally caught up with tire speed, the machine quit trying to vaporize the tread and began accelerating properly.
It was drivetrain engineering by controlled abuse.
No computer. No traction control. No clever clutch-management system. Just enough tire smoke to keep the engine, frame and rider traveling in roughly the same direction.
It worked.
The First One Went About 130
Potter took the Chevy-powered motorcycle to a local dragstrip in 1960. The first version still used a fairly mild 283 producing roughly 180 horsepower.
It went about 130 mph.
On a motorcycle a teenager had assembled around a junkyard automobile engine.
That should have been sufficient proof of concept. Potter had demonstrated that the machine could be built, ridden and returned with most of the important pieces still associated with one another.
A cautious builder might have declared victory.
Potter started improving it.
Art Arfons Saw the Business Plan
One of the people Potter encountered during those early years was Art Arfons, a man with plenty of experience making ordinary racing machinery look timid.
Arfons understood what Potter had built. It was not necessarily the foundation of a new competition motorcycle class.
It was an attraction.
If Potter could keep himself attached to the thing, promoters would pay to see him run it. That was a far better use for a V8 motorcycle than arguing with a rulebook over where it belonged.
Potter became the Michigan Madman, the motorcycle became an exhibition act, and dragstrip promoters acquired something they could advertise without explaining twice.
Then the Motorcycles Became Less Reasonable
Potter kept building. The first three machines carried the Bloody Mary name; later versions graduated to the much less reassuring Widowmaker.
Seven Chevrolet-powered bikes were built in all. The 283 grew into 327 and eventually as much as 350 cubic inches. Four carburetors appeared, followed by fuel injection. Gasoline gave way to alcohol and increasingly enthusiastic fuel mixtures.
A wide automobile slick eventually occupied the rear of the motorcycle, because once the machine already contained a Chevrolet V8 there was little dignity left to preserve in the tire department.
Power climbed from roughly 180 horsepower toward figures Potter estimated as high as 600.
Still two wheels.
The basic disagreement with common sense remained unchanged.
Steering Required Cooperation From Several Departments
Potter deliberately kept the motorcycles fairly short, generally under about eight feet, so they could fit into the back of a pickup. No transporter. No enormous crew. Load the Widowmaker, drive to the next strip and unload several hundred horsepower of poor judgment.
Once underway, the rear tire could continue spinning through much of the run. The motorcycle moved around, and Potter learned to control it with the throttle as much as the handlebars.
The rear wheel did not always regard following the front wheel as a binding contractual obligation.
That was part of the spectacle.
NHRA did not accept automobile-engined motorcycles in normal competition, so Potter made many of his appearances at AHRA tracks and other venues willing to book the Michigan Madman as an exhibition attraction.
The promoters had a simpler classification system.
If people bought tickets to see it, the class was full.
Eventually the Contraption Ran an 8.68
The bikes kept getting quicker. Potter took the act overseas, raced in Britain and Australia, crashed, broke bones, rebuilt the machinery and returned to the throttle.
In Australia he recorded an 8.68-second quarter-mile, quick enough to earn recognition in the Guinness record book. Later versions reached speeds well beyond 160 mph, with runs around 170 and beyond.
There was still a Chevrolet small-block between Potter’s knees, some tubing around it, two wheels underneath it and very little electronic assistance devoted to keeping the entire collection civilized.
The machine had begun as a teenager’s answer to a tape-measure question.
Now it was one of the quickest exhibition motorcycles in the world.
The Motorcycle Was Only the Beginning
Once Potter had demonstrated that engines did not necessarily need to stay with the type of vehicle their manufacturers had intended, the habit was difficult to contain.
He built Allison V12-powered cars, experimented with electric drag machinery, constructed a jet-powered trike and later moved into tractor pulling with enormous aircraft engines.
Most builders start with a vehicle and choose an engine suited to it.
Potter had already proved he preferred the question in the other direction: here is an engine; what can be built around it?
The Chevrolet motorcycles remained the machines that defined him because the idea required almost no explanation. A small-block V8 was large. A motorcycle was small. Potter put the first inside the second and went racing.
Anybody looking at the result knew something had gone wonderfully wrong.
The Tape Measure Said It Would Fit
The whole E.J. Potter approach is sitting right there in the tape measure. Most people could look at a Chevrolet V8 and a motorcycle frame and immediately list the reasons the two had never been introduced.
Potter measured them.
The dimensions looked possible, so he built the thing and dealt with the remaining details afterward.
No conventional transmission? Fine. The rear tire could absorb the launch. No radiator? The run would be over soon. Too much torque? Let the slick smoke until everybody reached an understanding.
His design philosophy was famously described as “ready, fire, aim.”
Hard to improve on that.
Everybody else saw a Chevrolet V8 that had no business in a motorcycle.
The Michigan Madman saw an engine that was only a little too long.