Farmers compete on many levels – whose corn grew best this year; which prize pig captured the blue ribbon; who has the straightest furrows in farm country. Not much an engine builder can do to influence any of those battles, but when it comes to power, American farmers are some of the most creative in the word.

Today’s tractor pulling might hardly be recognizable to farmers of yesteryear, but the premise is the same. Who can do the most work with the biggest tractor in the shortest amount of time. But really, can what these guys do with the monster machines they create really be called work?

We covered the NTPA’s stock tractor pulling classes in our August 2016 issue (“NTPA Tractor Pulling Powerplants – Big Size, Big Horses, Big Torque,” page 50) and in that article explained that “stock” relates only to the tractor’s external sheet metal. Since the sport’s originators would “Pull on Sunday, Farm on Monday,” a tractor that looks like a, well, tractor, can easily become a fan favorite. With the modified class, pullers build their reputation with sheer brute force.

Modified Pulling Tractors

Probably the biggest difference from other motorsports is the multiple engine configurations of the Modified Class. This class started out with single engine configurations, but found that more power could efficiently be made with the use of multiple blown alcohol engines joined precisely together. Through the years, the tractors have seen three, four, five and more engines. The complexity of joining these massive engines boggles the mind, and also the pocketbook.

The number and type of engines vary with the particular class. Just check the array of engines that are legal including automotive engines (such as Mopar and Chevy), V12 WWII Allison aircraft engines, and even Lycoming jet engines! And modified tractors sure don’t look like their Stock Class stock-appearing counterparts. They are more like an old style front engine rail dragster with the engine or engines sitting in front of the driver. And even though the modified tractors are different in appearance and size, they all must use the same 30.5×32 tires.

Modified Classes

Gregg Randall, general manager of the NTPA explained, “In 2012, we started the Light Unlimited Class for the modified tractors. The class uses the same blown alcohol engines as the other tractor classes. The configuration is up to the team, but they can’t exceed the 6,000-pound total tractor weight when using a pair of supercharged engines.

The 7500-pound Regional Class is extremely popular because of the variation of engines that can be used. To level the field, the class allows three blown alcohol engines with three 8-71 blowers or two with 14-71 blowers. It is also possible to use one or two Allison engines depending on supercharger size. And even turbine engines are allowed in certain groupings.

The exciting Mini-Modifieds do their exciting thing with just one blown alcohol engine. With all that power and a light vehicle weight, these machines have a tendency to get away from the drivers on occasion.

The Grand National Modifieds use the same technique of fewer engines with more boost. In this case it’s four engines with 8-71 blowers or three engines with 14-71 blowers. In almost all situations, the awesome three-engine configurations are blown Hemi engines. A maximum weight of 8,000 pounds is allowed. Finally, there is the Unlimited class, which is the biggest and baddest of the Grand National Class. Randall quipped, “Anything goes on the vehicle so long as it meets the 8,000 pound weight limit.”

Professional Modified Tractor Engine Builders

Fowler Engines has been a leader providing blown alcohol engines from its Columbus, OH shop for 40 years. Jeff Fowler explained that 30-40 percent of his engine customers buy the parts and pieces and assemble engines on their own. “In addition, we build rods, superchargers and fuel systems. However, I am concerned that there is too much technology in the engines that is making pulling a rich man’s sport.”

Hagadorn Racing Engines, Thompson, MO, specializes in turn-key blown alcohol engines. The company also supplies throttle bodies and fuel injection nozzles to customers doing their own engine build-ups. Concentration is on the multi-engine and mini-modified classes. Terry Hagedorn, who is one-of-one in this small operation, indicated that the customer can have his choice of blower brand in his turn-key engines.

JDF Performance Bulverde, TX, is another professional engine builder providing custom blown alcohol powerplants. All the engines have a Hemi flavor using either Veney, Allen Johnson or Brad Anderson heads. Some of the parts are from other manufacturers. Jeff Fagala explained that all the engines are flowed but there is no dyno in the building. JDF makes about 15 engines a year.

The Mets Machine Shop is capable of building diesel or gas engines, but the concentration is on the blown alcohol powerplants. Butch Gilger explained that about half of his customers buy the engine parts and assemble them on their own while others buy the turn-key engines from him in Mansfield, OH.

Miner Brothers, Stockton, CA is another blown alcohol building operation concentrating on the Unlimited and Mini-Modified classes. “We build some turn-key engines on customer request, but we also help pullers add to what they already have on their engines. We concentrate on the Hemi-style engines,” Bob Miner said. “The weak link I think in these engines are the over-driven blowers, which causes a lot of stress. The sport is pretty healthy in my mind. We sure are very busy.”

Sassy Racing Engines, Weare, NH, has the word ‘racing’ in its name. But it’s not compatible with its current activity of building blown alcohol pulling engines. The concentration is on the multi-engine modified classes. Sassy has been solely building Hemi engines since 1979 and uses a 526cid displacement. There is no fabrication done here with the turn-key engines built of parts from other manufacturers. Before pulling, the father-son operation of John and Brian Knox were heavily involved in national drag racing.

Professional Modified Tractor Engine Support Companies

As was the case with the stock engines, there are also a number of companies that provide the same type of support to the Modified blown alcohol classes.   

Alan Johnson Racing is a kingpin in NHRA Alcohol Funny Car racing, but its cylinder heads are one of the hot tickets for Modified pulling. A number of the blown alcohol pullers are using them today. They are either using used drag racing heads or are ordering them from Johnson directly.

Brad Anderson Enterprises, Ontario, Canada, a drag racing cylinder head builder, is very similar to the Alan Johnson operation above. Don Peterson explained, “We know that the blown alcohol pullers are using our stuff and they also order it right off the shelf. We are getting more interested in working with the pullers and it’s getting to be a bigger deal.”

Indy Cylinder Head provides support to both the diesel and alcohol tractors. In addition to its main cylinder head product, it also manufactures billet aluminum connecting rods, rocker arms and push rods. President Russ Flagle indicated that they are constantly looking for more air flow and reliability in their cylinder heads.

Ken Veney Heads is a high-tech provider of complete aluminum heads, which include the intake, valve train and more. They are a part of many winning modified teams engines. At the recent Farm Machinery Show, Veney heads were a part of five of the six four-engine tractors. Ken explained that the big open engines with his heads provided about 3,000hp while the restricted engines made about 2,500hp.

Homemade Modified Engine Building Examples

Unlimited driver Tim Bunnage explained that he started his pulling three decades ago. “Back then, I used drag racing and junk yard parts. Now I buy parts from Ken Veney and other companies and put them together myself. I’m getting about 2,700 horsepower from my engines these days.” He’s well known with his “Keeps-On-Tickin” machine.

Another unlimited driver is Dave Archer with his ‘Pioneer’ and he buys his engines directly from Fowler. “The Fowler engines get 2,600-2,800 horsepower, which is sometimes too much for certain tracks. I work around that detuning, taking out some timing, or run them a little richer.”

“Triple Trouble” is Ed Stahl’s three-engine 7500-lb. Modified. He laughed when he explained, “When I build these 526 engines myself, I know what’s in there and thus far I’ve been pretty successful. Some of the pieces I use include KB Hemi blocks, Indy Cylinder Head wedge heads, and Fowler rods. Been doing this for 30 years.”

Randy Davis with his 7500-lb Modified named “Running Bear” explained that he also built all the engines for his three-engine machine by himself. “Guess I’ve built about a dozen of them over the years. No way I can afford to buy new engines. I figure that I save about 20 percent doing them on my own.”

The patriotic “Uncle Sam” Unlimited belonging to Wayne Purser uses four and five-engine configurations. That fifth engine hangs out of the group of four. All the Pulser powerplants are home-built creations. “The brands I use are 8.71 Bower blowers, KB blocks, Miller Rods, Crane Cams, JE Pistons, Brad Anderson Heads and Ederle injection. They all seem to work well in my engine building. I’m also fortunate to have a dyno in my shop.”

John Gerhold drives a pair of Allison-powered Unlimiteds. The “Money Pit” has three of them, while the “Top Gun” has a pair. “These engines are very reliable and I have run them in 70 pulls without any maintenance. We are competing against blown Hemi engines, which are running at 9,000 rpms, twice what we are doing. In order to make our engines more competitive, we have substituted some modern components including 427 valves, Hilborn Injection, custom hollow cranks, overhead cams and I deleted the water injection.”

With the “Rambunctious II,” Duane Bergman is also an avid user of the 1940s Allison engines. He explained, “I got a ton of help from legendary Allison puller EJ Potter before he passed away. I replaced the engine’s stock supercharger with a pair of turbochargers. I also added electronic ignition and Hilborn Fuel Injection. It’s quite a different engine and is capable of 2,500-3,000 horsepower. I would guess that I have owned as many as 20 Allisons over the years.”

And finally, there is Don Deane and his “Plumber’s Nitemare.” There is no professional engine builder providing turbines, so Don has to possess the knowledge base himself, and he uses it well. The 7500-lb. Regional Modified has an engine package of two 50-year-old Lycoming Huey helicopter turbines along with a T-64 CH-53 helicopter turbine. The complexity of joining the turbine trio together is mind-boggling.

End of the Run

Even in this era of a slowing economy, it would appear that the Stock and Modified tractor classes are in a pretty solid position. A majority of the engine builders and supporting industries say they were in “pretty fair’” condition near the end of 2016.

There is a lot of availability for a tractor puller to choose one of several situations to acquire a pulling engine to fit his personal economic constraints. Surprisingly, the major engine builders realize that not all pullers can afford to purchase a turn-key engine. Buying the parts needed for the engine and assembling it themselves is just part of engine building in the pulling business. It’s amazing how much technology some of the home-built engine builders have to know.

Randall explained why teams can invest so much money in engines, reaching huge money, especially for the multi-engine modified tractors. “With the loads they have to handle, there is tremendous stress on them, probably more than any motorsport activity today. They concentrate on making the bottom end as strong as possible. The ever-increasing technology helps keep them going for a long time. But as any type of multi-engine modified puller will tell you, if one of those engines shuts down, you shut down everything immediately.”

An interesting phenomenon in modified tractor pulling is the great similarity with many of the powertrain parts with drag racing parts. This is surprising because the engines are about as different as you can get.

The tractor-pulling, engine-building conglomerate includes professional engine builders, home-built engine builders, engine support organizations, NTPA, and the pulling teams. They are all woven together and working together as one.

In this era of a somewhat flat economy, NTPA tractor pulling is currently one of the real success stories in today’s motorsports.