62-67 Flatheads 5/16/14 4:07 PM Page 65
Flathead Feature A stock 255 Mercury flathead in a ‘’50 Mercury.
lost.” Montgomery said another way to make big horsepower during the period was the use of the advanced Arden heads, which looked a lot like the later Chrysler Hemi heads. “Those heads could really breath a lot better than most other types,” he said. Montgomery explained that there was some unique engine building and utilization at Bonneville. “In 1952, I remember seeing a blown flathead which was topped by four carbs. There was a really wide set-up where a pair of hopped-up 239 flatheads had been joined crank-to-crank like multiengine pulling tractors are today.
The 255 Mercury Flathead Engine a 239 flathead engine that I bored and stroked out to 296 cubes. I added three Stromberg carbs to an Edelbrock manifold and ran 117 mph top speed at Bonneville. For about the first 10 years of my engine building activities, flatheads were my main concentration.
“I remember another hot flathead machine I built, putting a 239 with aftermarket heads, a hotter cam and dual carbs. Heck, there weren’t many drag strips during those days so I would drag race this car in downtown Dayton and a local radio station would broadcast them. It hardly ever
Engine builders particularly liked the 255cid flathead with its four-inchstroke crankshaft which provided the extra displacement. Usually, that crank was stroked an additional 1/8” up to 4 1/8” by rodders and racing types. The stock cams were replaced with aftermarket pieces, hot rod
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