445 CID: Ford's new 7.3-liter Super Duty gas V8 goes back to big inches

7.3-liters of displacement, 430 hp, 475 lb-ft of torque, Forged steel crankshaft

7.3-liters of displacement, 430 hp, 475 lb-ft of torque, Forged steel crankshaft

7.3-liters of displacement, 430 hp, 475 lb-ft of torque, Forged steel crankshaft

7.3-liters of displacement, 430 hp, 475 lb-ft of torque, Forged steel crankshaft

Ford’s latest engine for its Super Duty Trucks, aka F-250 through F-750, is a tried and true V8, America. It’s weird, however, as you get accustomed to seeing bigger horsepower and torque figures from smaller engines these days, to think its peak output of 430 horsepower at 5,500 rpm and 475 lb-ft of torque at 4,000 rpm seems a bit subdued. But that’s not really the point. “The engine has the largest displacement in its class,” according to Joel Beltramo, Ford’s manager of gas V8 engines, “and is designed to provide benefits in key areas like power, durability, ease of maintenance and total operating costs.”

Durability and ease of maintenance are the keys. The crankshaft is forged steel to start, with large main bearings. Ford employed a lot of turbocharged engine durability concepts in to this engine to give it an “overbuilt” structure. The rocker arms are steel too. The 7.3-liter uses a variable-displacement oil-pump to help keep all critical components cool and lubricated, not least of which includes the pistons, which receive cooling jets.

Bolted to the back of the 7.3-liter is a new 10-speed automatic transmission Ford calls Torqshift. There are roots connecting this transmission to the 10-speed GM and Ford co-developed and that is used in the F-150, but Ford claims that only seven percent of the parts are common with that transmission and none of them are torque-bearing. A higher-ratio first gear compared to the outgoing six-speed automatic helps the truck get moving from rest. And three overdrive gears give the powertrain computer lots of options to keep engine speed as low as possible, no matter the grade or load. Despite the extra gears, the 10-speed is the same length as the six-speed it replaces and only weighs 3.5-lbs more. It also has earlier torque converter lock-up and a “neutral mode” at engine idle to help save gas.

A valvetrain consisting of a single camshaft located in the block with pushrods extending out to two valves per cylinder may seem a bit old school. But it’s also proven, durable, takes less space and makes the engine easier to work on. The 7.3-liter is optional on F-250 and F-350 trucks and an upgrade from the 6.2-liter V8 offered as standard. A different tune version of the engine comes standard on F-450 chassis cab and other medium duty trucks, making 350 hp at 3,900 rpm and 468 lb-ft of torque also at 3,900 rpm.

The components that make up this engine and transmission look beefy, which is good because the trucks they’re mounted in are huge and heavy. While the power and torque curves look pedestrian to the latest turbo-diesels running around, they also look pretty darn flat, providing lots of torque at low revs. Besides, Ford has a new 6.7-liter Powerstroke diesel, with steel pistons, coming out soon. We can’t wait to learn more about it and share the news.

A higher ratio first gear and three overdrive gears make this transmission more versitle than the six-spedd automatic it repalces.

A higher ratio first gear and three overdrive gears make this transmission more versitle than the six-spedd automatic it repalces.

A higher ratio first gear and three overdrive gears make this transmission more versitle than the six-spedd automatic it repalces.




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