The largest gasoline engine ever produced by Ford for highway use is nearly forgotten today, but it’s worthy of a another look: the 534 Super Duty V8.
As we have seen, the engineers at Ford Motor Company were especially busy preparing for the 1958 model year, with the introduction of the Edsel and three complete new engine families: the FE series, the MEL V8 (see our feature on the MEL here) and the mighty SD series. While the SD was produced exclusively for medium-to-heavy-duty trucks and is virtually forgotten today, it’s an intriguing engine with some unusual features.
SD was short for Super Duty, and indeed, every aspect of this new Ford truck engine was engineered for severe use in commercial applications. The bore spacing was a huge 5.25 inches, easily accommodating a cylinder bore of 4.50 inches and supporting three available displacements: 401, 477, and 534 cubic inches. Each aluminum piston carried four chrome rings with a cast-iron insert for the top ring, and the spark plugs were coolant-jacketed to reduce fouling and extend plug life.
The entire cooling system was remarkably elaborate, featuring front and rear thermostats and a three-stage coolant-circuit strategy to precisely manage engine temperature. When water temperature reached 160 degrees, both thermostats opened to allow full coolant flow of 12,600 gallons per hour from the gigantic water pump. The lubrication system was equally beefy, with an internal oil cooler and an 11-quart oil pan.
While the SD shared no major components with any Ford passenger car engines, it did share one interesting design feature with the MEL V8. There were no combustion chambers in the cylinder heads. Rather, chambers were formed by machining the deck of the block at an obtuse angle. (The Chevrolet 348/409 V8 also shared this chamber design; see our feature here.) In order to reduce piston speed, the bore/stroke ratio was remarkably sporty for a truck engine, and as with many racing engines of the period, the exhaust valves were sodium-filled.
Rated at 226 hp, 253 hp, and 266 hp respectively, the SD-401, SD-477, and SD-534 V8s were used in countless truck applications between 1958 and 1981, including Ford’s C, H, L, and N series trucks and the larger F series vehicles. An industrial engine package was also offered, which included a skid-mounted engine with all accessories in a metal enclosure. All SD engines were produced at Ford’s Cleveland engine plant in Brook Park, Ohio.
While the Super Duty was in every way a workhorse, not a racehorse, the giant V8 did find at least one glamorous application. In the ’60s and ’70s Seamaster Marine adapted the SD-534 for use in large pleasure boats, including Chris-Craft and others. At the top of the range was the Super Seamaster 534-TI-B (below) that featured twin turbochargers with intercooling and a rated output of 400 hp and 657 lb-ft of torque. It’s said that some of these 534 Seamasters are still in regular use.
Loved hearing the 534s sing, as the Walters Snow Fighters cleared the streets in our city!
The SDs had a presence but they weren’t as plentiful as the big International engines. The V-Line Binders were everywhere it seemed. However there were some SD engines made it to our region. I’ll always remember the solid lifters and the instructions of setting them hot, with the engine running. The general attitude was to set them cold and add a couple thou. In the later 70s Ford brought out the 475 which was essentially a 477 SD with some smog equipment. Some made their way onto the farms in the form of the LT800 truck. It probably would’ve been more of a success if diesel power hadn’t started to gain a substantial foothold…
One much appreciated SD feature was the block’s integral cast pad for sturdily mounting of an brake air compressor, if needed. Far superior to the typical “afterthought” mounting arrangement of many engines.
Typical “afterthought” compressor mounts were a maintenance headache to try to keep a heavy pump’s bracketry tight and not cracked.