How The Hartsock/Wile Ultra Street Mustang Broke The 4.40 Barrier With Holley Dominator EFI

10 min read

How The Hartsock/Wile Ultra Street Mustang Broke The 4.40 Barrier With Holley Dominator EFI

10 min read

It has taken several years for the barrier many drag racing observers thought would stand tall against penetration – the 4.40 mark in Ultra Street – to tumble down. A pair of savvy racers using a Holley Dominator EFI system on their nitrous-injected Ultra Street Fox Mustang cracked the barrier with a 4.493 at nearly 156 mph during the Yellowbullet Nationals at Cecil County Dragway.

The team of Connor Hartsock (27) and Dylan Wile (28) represent the next generation of drag racers, with Hartsock providing the tune-up talent and Wile hitting the tree hard as the wheelman. But their story starts several years ago; the pair met through Snapchat and forged a friendship that has endured, turning into a record-breaking race team partnership.

“It was pretty exciting; I wasn’t sure if the car was going to do it or not,” says Wile.

“Connor told me he shortened the ramp by two tenths, and I looked at him like, ‘What are you trying to do to me here?’ He told me just to drive it. I didn’t believe the board when I saw it; I passed the board and thought there was no way it was right.”

Hartsock Wile Mustang working on engine

A few seasons ago, after being influenced by another current racer — Ultra Street competitor Steve Beaston, Jr. — Wile decided to go Ultra Street racing with a nitrous-injected small-block Malibu. That car, tuned by Connor and equipped with an engine built by Connor’s dad, Bob Hartsock of Hartsock Racing Engines, was in no shape or form a class front-runner.

“We were slow; we ran 5.0s. I was tuning on it, and it was Dylan’s car and engine. But we had a blast — I think he had $6,000 in the engine,” says Hartsock.

“Then he traded the small-block and transmission for a big-block engine. After testing it on the dyno — where it only made 900 horsepower — he gave it to my dad to look over. He ended up keeping the crank, block, and rods, and we did pistons, heads, and intake. Two years ago, we went 4.70s with it and were class-fillers, but we were still having fun.”

The competition level in the class whet their appetite for more. Around the same time, Wile realized that the Malibu’s chassis wasn’t ideal for Ultra competition and sold the car.

“The chassis wasn’t the best. We just couldn‘t get it to work right. The cage wasn’t welded to the frame like it should have been, so it was flexing real bad. I don’t have the money to build a competitive motor and car, so I got rid of the car, and that’s when I bought all of the Holley stuff. The Malibu only had a 7AL box, so I splurged on all of the Holley stuff to help us get ahead since we were going to team up,” says Wile.

Hartsock Wile Mustang marker lights

Through a friend, they found the Mustang in these photos as a shell for $2,000. After making the purchase and taking the body back to Wile’s house, the idea popped up to stick the Ultra Street-legal big-block into the Mustang and move forward. Although the car had a roll cage at that time, they pulled out most of the cage and redid the entire car. Hartsock — who works as a fabricator and machinist during the day — drew the chassis into the CAD system at work, laid out how he wanted the chassis to look, built the rear, and then they did all of the work at Wile’s father’s garage on a two-post lift.

After many all-day-long Saturday sessions of welding, wiring, and fabricating, the team finished the car by the end of last summer, and Hartsock piloted it at its first couple of races. With initial tuning help from well-known Holley EFI guru Mike Thompson of TNT Performance Automotive and Hartsock taking over the tuning after that, the team recorded a 4.56 best pass for the 2020 season. This performance showed them that there might be enough in this simple combination to get into the 4.40s, and so they set out at the beginning of 2021 to do just that — become the first team to break that barrier.

“The Holley was all new to me. We went to Mike and told him we needed to get it onto the dyno so we could make the three fall races last year. We wired the car in two afternoons with the help of another friend and then went to the first race, where we broke into the .60s our first time out with the car. Then we went to VMP and went a 4.63, then back to Cecil, and on the tenth pass we went a 4.56 [at the end of last year],” says Hartsock.

From the driver’s perspective, Wile likes consistency. It is interesting to note that many top performers — regardless of discipline, from baseball to drag racing — are often routine-oriented. Whether it’s a hitter taking the same number of practice swings before entering the batter’s box or a driver following the same routine before firing the engine for the burnout, consistency is vital.

“I like having a routine and not breaking it; we do the same thing from the time we leave the trailer to the time I stage the car in the beams. I want the same people doing the same things to the car. I want the same person helping me put my straps over, the same person checking the tire pressure every time. If someone different comes over to give me a fist pound, I won’t do it. It throws me out of my routine. And I let the other driver prestage, and then go in and light both bulbs so the car can settle on the transbrake,” says Wile.

With the knowledge in hand that they could run 4.50s seemingly at will, they went into 2021 with a plan to be the first car into the 4.40 zone, and as we see, nothing could stop them.

“I’m usually conservative, and this race was the first time I’ve not been conservative. The cars are going to slow down from here through the rest of the year. I jumped the gun to go .40s because we knew that the rest of the year, we wouldn’t get the chance again until September. We wanted to be the first, and I probably could have gotten there without hurting it if I had three more passes, but we didn’t have three more passes. When you get into race mode trying to go rounds, you have to be conservative. In qualifying, once you’re in the field, there’s no being conservative. I just threw it to it to go .40s, even though it hurt it,” says Hartsock.

The engine is already out of the car and under repair at Hartsock Racing Engines. They nipped one piston running the big number, but they have spares, and the engine will be back together shortly — likely before you even read this.

The 1992 Mustang is powered by a 588 cubic-inch big-block Chevrolet, featuring a World Products Merlin block, Callies forged crankshaft, MGP connecting rods, a Comp Cams camshaft, and Diamond pistons. An Edelbrock manifold feeds the air from the Holley Dominator EFI throttle body into the Brodix BR X 20 cylinder heads. Hartsock tunes the Holley Dominator EFI system to maximize the performance from the Fast Lane nitrous oxide system.

Hartsock Wile Mustang burnout

“My father used to tune on Pro Mods; he was a big-block nitrous guy. When Dylan still had the small-block, and we saw that the rules were going to allow the big-block in, Dad thought the switch would be the ticket to us being competitive on a budget. To build a big-inch small-block that runs up front is a ton of money,” says Hartsock.

Keith Performance Transmissions assembled the Turbo 400 transmission. The torque converter manufacturer is undisclosed (hey, the guys tell us they have to have some secrets!), and Hartsock designed and built the rearend housing before filling it with Mark Williams and Strange Engineering components.

After struggling with the Malibu’s performance, they knew that it was critical to invest in superior suspension components during the build of this car. To that end, they selected dampers from Adam Lambert at Precision Racing Suspensions.

The car sleeps at Dylan’s house, and he performs the maintenance on it between events. With an hour and 20 minutes separating the pair (and Hartsock with dad responsibilities to fulfill), they find a way to make it work.

Hartsock Wile Mustang family photo

Along the way, the pair have pooled their resources to gather up the necessary parts to break barriers and, in the process, assembled a racing family with extensive experience. From Connor’s dad building the engine to Wile’s dad (Backyard Customs) painting this car, to fellow Ultra Street racer Kenny Keith building the transmission and others donating their time and effort to will this team into the record books, each member of the family contributes in some way to the success of these youngsters. Perhaps the most impressive part of their success is the internal drive it takes to stay on the pace at this level.

“It’s a team effort,” says Hartsock.

“We have just as much fun now as we had when we were going 5.0s with the green Malibu class-filler. If we stop having fun, it’s not worth doing.”


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