Dirt modified driver Hunt Gossum never lived in a world where NASCAR’s premier series was called the NASCAR Winston Cup Series. Yet, the major components of the engine the 15-year-old driver uses — the engine block, intake manifold, and cylinder heads — all come from the Winston Cup era. In fact, the year on the cylinder heads, 1994, predates Gossum by ten years.
Gossum’s father, Todd, traced the lineage of the parts to the Penske Racing South NASCAR Cup team when they fielded a car for future NASCAR Hall of Famer Rusty Wallace — a driver that Hunt never saw race.
In 1994, Wallace scored eight wins — the most that season. He fared well on the short tracks, too, with two victories at Martinsville and one at Bristol. The Gossums, who acquired the pieces from Roush Yates, wondered if they could translate the success Penske had on short tracks 25 years ago and apply it to dirt bullrings today.
Built to Be Cool
The 410ci Ford R engine block is based on a Ford 351ci Windsor. It is cast out of compacted graphite iron, which makes it stronger, yet lighter, than conventional iron. However, since the block and cylinder heads have a relatively large water capacity, it weighs nearly 10 pounds heavier than Gossum’s other engine, a USMTS-spec 430ci Ford.
The engine keeps so cool that at one point, the Gossums reduced their customizable radiator fan to only two blades — and the engine’s water temperature rose to only 175°F on the track. While Gossum races nowhere near the 400- to 500-lap (or mile) endurance races of NASCAR, a cooler engine offers other advantages, according to their engine builder, Scott Fischer, of SPEC Racing Engines in Huntingburg, Indiana.
“It’s not just keeping it [the engine] cool; it’s eliminating hot spots,” Fischer said. “If you get a hot spot in a cylinder head, it’ll detonate. There’s no efficient way to tune for cylinder hot spots. If you have to over-tune to keep the engine alive because of a bad cooling system — such as backing the timing off or adding fuel to the air-fuel mixture of the carburetor — you’re hurting the horsepower.”
The heads look bulky, but the casting is actually fairly thin. It just has a lot of water capacity in it. – Scott Fischer
The Ford C3 cylinder heads resemble those of a Ford 351ci Cleveland engine. Like most Ford cylinder heads, the Ford C3 cylinder head evenly spaces out the exhaust ports. This creates less hot spots than a traditional Chevrolet head, which places two exhaust ports together in the middle. The heads have another cooling feature.
“We were going to do some lightening on [the cylinder heads] — the heads look bulky,” Fischer said. “But the casting is actually fairly thin — it just has a lot of water capacity in it.”
The intake manifold, which Fischer said resembles most intakes today, also helps with cooling, but in a different way.
“It’s an air-gap intake,” said Fischer. “It’s got a valley tray underneath, so the air can flow all around the manifold, which keeps it cooler. The cooler the inlet air, the denser it is when it compacts in the cylinder, which makes more horsepower.”
The engine block uses smaller main bearings, from a 302ci Ford. Fischer said this reduces the need for oiling.
“The smaller the main bearing and the smaller the rod bearing you use, you have less bearing speed, so it doesn’t require nearly as much oil to keep the crankshaft alive.”
With less oil, comes less windage — a situation where oil wraps around the crankshaft, which robs horsepower. However, Fischer found he needed to add an external oil pump, in lieu of the one commonly found inside the oil pan, to increase oil pressure.
“We have to run an external [oil] pump because it has a real small distributor gear,” said Fischer.
NASCAR teams use a dry-sump oil system, but most dirt modified sanctioning bodies require a wet sump. Fischer had to innovate to move the oil pump.
“We built a special pickup tube inside the oil pan, hooked a line to it, and then ran the pump off the back of the engine,” Fischer said.
How It Feels
Hunt has raced modifieds since he was 10 years old. During that time, he’s only run two types of engines, both Fords — a 430ci USMTS-spec engine, and the 410ci Ford using old Cup parts. Todd said the USMTS one produces around 700 hp, with 630 lb-ft of torque. The other generates close to 800 hp, with 640 lb-ft of torque.
“The USMTS engine doesn’t have the top-end,” said Hunt. “If I get in a rut or push, I can’t [throttle] out of it. It’s harder to overcome a mistake.”
Overall, the engine is smooth and consistent; that’s why I love the motor. – Hunt Gossum
Despite more overall power, Hunt said the engine delivers it controllably.
“Overall, the engine is smooth and consistent; that’s why I love the motor,” Hunt said. “It’s very predictable, driveable.”
Fischer felt the difference between the two engines primarily comes down to the cylinder heads.
“An engine is basically an air pump,” said Fischer. “The USMTS-spec head restricts the amount of air in a cylinder head. The USMTS-spec engine is actually bigger. The USMTS-spec engine is actually bigger. He’s [Hunt] feeling the power difference [due to] the cylinder head.”
On the Track
Hunt used the Ford engine with Cup components to visit victory lane five times this year, including a DIRTcar Modified Nationals win at Oakshade Raceway in Wauseon, Ohio. They raced it 50-plus times before a piece of debris on the track put a hole in the oil pan in the fall. They plan to rebuild it for next season.
“We’re Ford people,” said Hunt. “I love the engine. It’s perfect for what we do.”
Fischer agreed with the Gossums’ choice for the foundation of their engine.
“It’s not like it’s old, antiquated stuff,” Fischer said. “They still ran this stuff in the 2000s. The technology back then was good. The castings and the manifold are what make the power — you just put new parts in those things, so the engine doesn’t break. It’s older technology, but it’s probably better than what most guys are racing.”