This Ex-Jeg Coughlin Jr. Pro Stock Cavalier Now Packs A Gen III HEMI.

What would you do with an ex-Jeg Coughlin Jr. Pro Stock Cavalier? Most racers would shove a big-block Chevy in between the front tubes and go Top Sportsman or Competition Eliminator racing. Well, Jack Henderson and Mike Schaefer had a different plan that involved a Gen III HEMI and a supercharger.

Henderson is a long-time Mopar fan and racer. He started racing back in 1958 and has driven numerous race cars during his career. The 2003 Cavalier first entered his life when a friend was running it in Competition Eliminator and asked Henderson for help. The owner went another direction with his racing program, so the car sat until Henderson purchased it and pressed it back into service.

Schaefer, owner of Mod Shop Race Cars, has helped Henderson with the Cavalier for some time. The car was originally campaigned with a 500-cubic-inch Pro Stock engine, but the team moved away from that due to the valvetrain maintenance requirements.

A nitrous-huffing 632-cubic-inch big-block Chevy replaced the Pro Stock engine, but that really wasn’t a good fit for the team either.

“We understood the engine, made good passes, and won some races, but it was a lot of work. There is a lot of maintenance involved to keep a big-cubic-inch nitrous engine healthy at this level. Dealing with the nitrous was not ideal either for our program, so we needed a change,” Schaefer explains.

The goal was to race the Cavalier in Quick 16 shootouts, 4.70 index races, and Top Sportsman as well. Schaefer had experience with Gen III HEMIs since his Dart is powered by one, and Henderson is a Mopar man. So, the decision was made to move to a modern HEMI as a powerplant for the Cavalier.

Schaefer’s Dart turned into a seven-second monster after he made the switch to a Gen III HEMI from Blackbird Performance. To push the Cavalier into the performance zone required for the racing they had planned, Schaefer knew they would need a pretty nasty modern HEMI.

“We needed a lot of rpm for this application. So, we worked with Geoff Turk at Blackbird Performance and settled on what is basically a Drag Pak engine. This little guy wants to really rev, and it’s a hydraulic cam engine. It makes around 1,700 horsepower, so in a light ex-Pro Stock car it really scoots,” Schaefer says.

The change was made, and the Mopar men were in business.

Controlling the HEMI-powered Cavalier is a Holley EFI system. A K&R Pro-Cube Plus delay box was added to the car for bracket and Top Sportsman racing. The same Whipple supercharger you’d find on any Factory Stock Showdown car is what rests on top of the Gen III HEMI under the hood of Henderson’s car. The rest of the Cavalier remains pretty much the same as it did when Coughlin wheeled it at NHRA national events.

What makes Henderson’s Cavalier so interesting is that this isn’t a package you typically see at the track. There have been a few doorslammers in Top Sportsman that have received a COPO-based LS engine, but none with a Gen III HEMI. While that may not seem like a big deal, there’s no data on what the car will do or how to build the rest of the combination out for maximum performance.

That lack of information provided a challenge for Schaefer and his team the first time they took the Cavalier out.

“When we took the car to the track for the first time, we found out the converter was a little off. This car is light, that engine needs rpm, and it really struggled with what we had in there. Thankfully, we got some great data from the trip and were able to make adjustments,” Schaefer explains.

The next time the Cavalier went to the track with Scott Schaefer, Mike’s son, behind the wheel, the outcome was much different. A new converter and a few tune-up changes netted a slew of low-4.50 eighth-mile runs in the 150 mph zone. When Schaefer put the car in bracket-race mode, it started printing 4.51 tickets like clockwork.

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“We’re happy with the progress we’ve made with the car. This combination is going to be great for Top Sportsman and index racing. These Gen III HEMI engines are very easy on parts, and you don’t have to stress them to make a lot of power. I think this car is going to be very competitive once we get it fully dialed in,” Schaefer says.

Most people are happy staying on the path of what’s known. Clearly, Jack Henderson and Mike Schaefer have no problem stepping off that path. Taking a Pro Stock Cavalier and stuffing a supercharged Gen III HEMI under its hood isn’t the first choice most people would make, but it seems to be working out great for Henderson and Schaefer.