Jason Hamstra’s Mustang is a Pro Mod Powerhouse; NMCA Feature

By Mary Lendzion, NMCAdigital.com

After spending time in the cockpit of two different bracket dragsters, Jason Hamstra introduced himself and a six-second ’63 Corvette with a roots-blown Hemi to IHRA Pro Mod in ’05.

“I was the first person to run a torque converter-driven transmission in a Pro Mod car at a time when people were running clutches,” said Hamstra, of DeMotte, Indiana. “I won a lot of races with it.”

While staying in the same class and keeping the same combination, he moved to a ’68 Camaro in ’08 followed by a ’70 Duster, which also saw ADRL Pro Extreme action, but with a screw-blown Hemi, and it was with the latter that he won a championship in ’11.

“After we won the championship, we ran a dragster with a roots-blown 481X Alan Johnson engine in ’12 in a series at local tracks called Asphalt Warz and we were 3.70s in the eighth-mile, but there weren’t a lot of places to run the dragster, and we decided to stop running it and focus our efforts on getting a Pro Mod car,” said Hamstra.

Two years later, after deciding to enter NHRA competition, he bought the Dan Page-built ’10 Mustang he currently has, and made plans to outfit it with the 481X Alan Johnson engine, roots blower and mechanical fuel-injection from the dragster.

“It was the car that Mike Janis ran in NHRA Pro Mod in ’11 and ’12, and I bought it as an all-white roller in the winter of ’12 and took it to Chris Duncan in Illinois over the winter,” said Hamstra. “He had to make motor-plates and headers for it.”


Meanwhile, he and his dad, Kevin Hamstra, had begun freshening up the engine and set it up with higher-compression J&E pistons and piston rings. They also had begun wiring the car and plumbing, about which you can Read More Here, it for the fuel lines and oil system.

“Wiring and plumbing is a pretty sizable job, but I’ve been doing that stuff for a long time,” said Hamstra. “Once you have a system for doing it, it goes pretty quickly.”

Upon getting the car back from Duncan about a month later, Hamstra and his dad introduced the engine to the engine bay, and backed it up with a converter-driven Lencodrive transmission.

“The engine pretty much dropped right in and fit,” said Hamstra.

What followed were some changes to the suspension, including taking the car’s wheelbase from 112 inches to 114 inches.

“Chris Duncan make the four-link bars longer and then moved the new shock mounts two inches back,” said Hamstra. “Then, I set up the four-link and Strange shocks and Strange shuts.”

The car was then wrapped by Sticker Dude Designs, and Hamstra headed to US 131 Motorsports Park in Michigan to test in the spring of ’13.

“For the mechanical fuel-injection, you bypass fuel back to the tank and control fuel pressure to the system and nozzle areas to get the fuel just right, so we were working with that,” said Hamstra. “I was making 330 and eighth-mile runs, and it took a few runs to learn about the new car, but it went pretty well. It’s a good car that was built well, and you can tell that by how it handles.”

He jumped into the NMCA Kooks Pro Street — now called Kooks Pro Mod — ranks at the 8th Annual Nitto Tire NMCA/NMRA Super Bowl of Street Legal Drag Racing event at Route 66 Raceway in Illinois in July, where he qualified thirteenth with a 6.62 and 226 mph and posted a 7.42 at 135 mph to Steve Summers’ winning 6.20 at 249. He rounded out his ’13 race schedule with NHRA Pro Mod.

“The ADRL and NHRA rules were pretty much the same, and for NMCA, we could have taken some weight out to go from 2600 to 2500 pounds, but we just left it in so we would be in the same trim at all of the races,” said Hamstra. “A lot of the same guys run between the series, and the competition is pretty tough.”


Hamstra last season got the car to run as fast as 6.10 and 235 mph, and after deciding to ramp up his efforts, he over winter purchased a 521 cubic-inch Hemi engine from Mike Janis stuffed with a Bryant crank, GRP rods and Diamond pistons, and topped with MBE heads and Hogan’s aluminum sheetmetal intake.

“We already had the roots blower, so we were all set there,” said Hamstra. “We could have kept the 481X engine but there has been a lot more research-and-development done on the Hemi over the years and it made sense to us.”

Hamstra, who chose to continue using the Lencodrive transmission he had been running, elected to leave the engine as-is, as it had made 2700 horsepower on the dyno while in Janis’ possession.

“It was all set up for running Pro Mod, and all I had to do was have some new headers made and re-plumb the oil and fuel system, since the 481X had a wet-sump oiling system and the Hemi had a dry system,” said Hamstra

hamstra3During a test session at Bradenton Motorsports Park in Florida in March, he posted a 3.87 at 193 in the eighth-mile with the new combination, followed by a 3.86 at 194 mph.

“It ran well right away, and we were happy with it,” said Hamstra. “At the Gainesville NHRA race right after that, in the first qualifying pass, it went 3.86 at 196 in the eighth-mile and then 5.86 at 247 in the quarter-mile on the same pass. We qualified fourth with the 5.86 at 247 mph, and even though we shook the tires in the first round and lost, we were feeling good about running as well as we did at the first race of the year with a new combination.”

After that, he headed to the NHRA event in Texas, where he ran into ignition issues which followed him to the Inaugural Quick Fuel Technology NMCA Muscle Car Nationals event in May in Illinois, where he qualified second out of a field of fifteen with a 5.94 and 244 mph. He advanced to the semifinal.

“There were a lot of cars there and it was a tough field,” said Hamstra. “We were the only supercharged car there among all of the turbo and nitrous cars.”

He followed that with a trip to the final at the NHRA event in New Jersey, despite the continued ignition issues.

“We qualified twelfth and had Rickie Smith in the first round,” said Hamstra. “He went 5.83 and I went 5.86, but I beat him on a holeshot. I was glad to make it to the final even though I was having intermittent ignition issues.”

Confident, he rolled into the 9th Annual Nitto Tire NMCA/NMRA Super Bowl of Street Legal Drag Racing presented by Strange Engineering at Route 66 Raceway in Illinois in July, where rain forced an early end to qualifying. That trimmed several racers who had not had a clean hit — including Hamstra — from the full field.

“We tested a few weeks after that because we wanted to work at getting the car down the track in warm-weather conditions since we hadn’t run it very much in warm-weather,” said Hamstra. “It was a productive test session and we went 3.93 at 192 and 3.89 at 193, which was good considering how hot it was outside at the time and the fact that I was shifting early to be easy on parts. I basically just wanted to get the short-end of the track figured out.”

Now Hamstra, who minces no words when he says he relishes this level of competition, is preparing to take part in the 13th Annual NMCA World Street Finals featuring the 8th Annual Chevrolet Performance LSX Shootout at Lucas Oil Raceway in Indiana on Oct. 9-12, 2014.

“It seems that in drag-racing, you just kind of keep moving up because when you get used to the speed, you want to go even faster,” said Hamstra. “I love Pro Mod cars and I’m happy to be in a fast car. It’s really very neat.”

Owner: Kevin Hamstra
Driver: Jason Hamstra
Class: Kooks Pro Mod
Hometown: DeMotte, Indiana
Occupation: Engineer
Crew: Rob Olenick, Karen Hamstra and Kevin Hamstra

Engine: 521 Hemi
Bore: 4.470
Stroke: 4.150
Crank: Bryant
Rods: GRP
Pistons: Diamond
Heads: MBE
Valvetrain: Manton rockers and pushrods
Cam type: Custom Bullet camshaft
Power-adder: 14-71 Kobelco Supercharger
Transmission: Lencodrive
Torque converter: Coan
Rearend: Mark Williams

Chassis: Dan Page
Suspension (front): Strange struts
Suspension (rear): Strange Shocks
Brakes: Mark Williams carbon fiber
Wheels (front and rear): Weld
Tires (front and rear): Goodyear
Aftermarket body modifications: ‘10 Roush Mustang carbon fiber body
Vehicle weight: 2600 pounds
Quickest ET: 5.86
Fastest mph: 247
Best 60-foot: .961
Sponsors: Coan, Lencodrive Racing Transmissions, Manton Rockerarms

This feature and more photos of Hamstra’s car are in the Oct. ’14 issue of Fastest Street Car.