The Horsepower Monster via YouTube

Ford Flathead V8s are of archetypal importance to the hot-rodding community, even though they were never that powerful by today’s standards. They gave Regular Joes access to relatively high performance numbers throughout their production run, which lasted about two decades starting in the early 1930s. Some of them are still alive and kicking, but very few make 722 horsepower on the dyno like this one built by Keith and Jeff Dorton at Automotive Specialists.

It’s a land-speed racing engine that just so happens to run a Procharger F1-R centrifugal blower and a unique Ardun overhead valve setup. The latter is arguably the most interesting part of the build as only 200-250 sets of Ardun heads are believed to have been made. Whereas the most output a stock Flathead ever mustered was around 110 hp, those modified with these special heads produced roughly 160 hp.

The Horsepower Monster via YouTube

Jeff Hunnycutt collaborated with Keitha and Jeff Dorton to feature the power plant on Hemmings as well as his own YouTube channel, The Horsepower Monster. He explains that while the Ardun heads were awesome for making more power, they’re so big they didn’t always fit under the car’s hood. That was only one issue builders had to solve as swapping a pushrod engine to run with overhead valves caused enough of a conundrum already.

Oh, and they cost $500 back then, which is roughly equivalent to $8,500 in today’s money. If you want a new set of Ardun heads, a fellow named Don Ferguson owns the rights to build them and related accessories. He’ll apparently sell you a set for $15,950 if you’re serious about building a period-correct, high-po Flathead.

Anywho, the Dortons went through a lot of trouble to make this engine work with the new-age forced induction setup. The packaging is admittedly strange but they had to configure it so everything fits inside their 1929 Ford Roadster. That’s why the intercooler sits a little cockeyed above the blower.

The Horsepower Monster via YouTube

The Horsepower Monster via YouTube

The Horsepower Monster via YouTube

So many modifications were made for this Flathead to run the Ardun heads and make this sort of power. It has modern main seals with plenty more trick machining internally, and the car runs a Chevy flywheel and clutch. The goal is to break the Blown Fuel Roadster and Blown Gas Roadster records at Bonneville, which currently sit at 203.4 mph and 208.24 mph, respectively.

The Dortons are said to be confident in this setup’s ability to set new speed benchmarks. They’re running just 10 pounds of boost as-is, and while the Procharger is capable of a lot more, there may be no need. Output crested at 722.8 hp and 654.5 pound-feet of torque, and that dyno test was cut at 5,800 rpm as the horsepower seemed to keep climbing.

There’s so much to this engine build that it’s worth watching the video in full. I’ve embedded it below so you can learn all there is to know from Hunnycutt and Co.

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The post Boosted Ford Flathead V8 Makes 722 HP With Rare OHV Swap appeared first on The Drive.

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