Steve’s Supercharger Blog
Supercharged Ford Flathead Engines
The most common originally available aftermarket flathead superchargers were manufactured by McCulloch Engineering Company. Many of these units found their way into vehicles designed for heavy duty applications, such as dump trucks, delivery trucks and tractor-trailers. These uses were referred to as high-power applications.
The other big sales application was of course for Ford flathead V8 engine automobiles. These cars were called Hot Rods and the driving force was more speed. Period advertising promised a 38% horsepower increase, better gasoline mileage, and longer engine life. Although the earliest McCullochs were not as dependable as users expected, the company soon got past that problem by introducing oil lubrication of the drive gear by motor oil. With internal lubrication dependability was no problem.
McCulloch superchargers usually introduced 50 “free” more horsepower. The extra power transferred into seconds less in quarter mile contests. The other benefit was a smoother idle when mounted on an engine employing an aggressive cam profile. Flatheads, so equipped were proven to produce up to 150 HP.<br><br>Running with a McCulloch normally was more successful if the engine was down-tuned to a 7:1 compression ratio, instead of the 9:1 normally found. Pre-ignition, or engine ping was a common problem when compression was too high, even when burning the highest octane gasoline available. Another way to combat ping was water/alcohol injection, usually a mixture of 50% water and 50% methanol.Some hot rodders called these solutions “snake oil” and would not employ them.A major benefit of the injection solution was that it served to cool the intake manifold, and clean carbon build-up from the cylinder, valves, and pistons.
Original McCulloch superchargers appear on eBay from time to time, and even original water injection equipment is available for purists. These units when they become available are usually in the several thousand dollar price range.
Newer blower systems, which are similar in design concept, but much improved, are available from companies such as Roadrunner Engineering and Cornhusker Rod & Custom. The land speed record for a flathead is currently held by a car powered with a Vortech blower. It has made record runs near 300 MPH using a blown flathead. Supercharged flatheads are serious business at that speed.
A popular place to see actual Ford flatheads with installed superchargers is the Ocala, FL drag racing museum, run by Don Garlit a well known racer from earlier times. Today, a number of cars are available with modern superchargers or turbochargers with better performance characteristics due from the introduction of electronic fuel injection (EFI). Among them are ZO6 Corvettes, 5.0 Mustangs and some Cadillacs.