A Little More: 1977 Jeep CJ-7
1,400-Horsepower AMC-Powered Mud Racer
"If a little is good, a little more must be better," Richard Dunavant said when describing how his '77 CJ-7 ended up a dedicated mud racer. Richard previously owned a whole slew of Jeeps, including a few different CJ-7s, a couple of Grand Cherokees, four XJs, and a J3000. In 1989, though, he sold his '82 CJ-7 because it did not fit the needs of his young family. But Richard was never cured of his Jeep affliction, and three years later his wife Julie helped him drag a CJ frame into their garage so that Richard could start a father-son project with his son Richie. When Richard and Julie lost Richie to cancer 17 years ago, rather than sell the Jeep, Richard decided to make their CJ-7 bigger and better than ever in Richie's memory.
The foundation for Richard's mud machine is the original '77 frame. It has been considerably reinforced with multiple crossmembers and a full eight-point, 1.75-inch diameter, 0.095-wall chromoly rollcage from Mike Graham at Virginia Speed Race Cars. The leaf springs were ditched ten years ago and replaced with coilovers to help the tires hook as the Jeep evolved into a serious mud racer. The fronts are only dinky 14.5x15 Sand Tires Unlimited tires on 15x10 Weld Drag Lites, but the rears are all business. The 15x18 Real Wheels are mounted with a pair of heavily cut 39.5x18.5-15 Super Swamper Boggers for unmatched traction. Virginia Speed Race Cars built the front three-link from 11/4-inch, 0.095-wall chromoly tubing and good 3/4-inch Aurora chromoly rod ends. Strange coilovers keep the whole thing up in the air. Out back, a set of Afco coilovers work in conjunction with a four-link utilizing 0.095-wall chromoly tubing and 3/4-inch Aurora chromoly rod ends. The rear lets the Boggers hook hard enough that even with a 106-inch wheelbase, a 7-foot-long wheelie bar is often put to good use. After all, you don't want the front tires getting too far from terra firma when heading down the track at over 100mph.
A dialed-in suspension is an important component in getting the Jeep to hook up, but it is only part of the equation. It takes some serious horsepower to turn cut Boggers fast enough to make a successful racer. Motorvation comes from an all-aluminum 499ci Indy Racing AMC engine with Indy aluminum cylinder heads, Jessel rockers, and a huge Comp Cams roller camshaft. Barry Allen Racing Engines built the big-displacement AMC engine with a Moldex crankshaft sporting a 4.15-inch stroke, GRP aluminum connection rods, and Diamond Racing pistons for the 4.375-inch bore. The combination squeezes out a 14:1 compression ratio and is fed by a huge 1,200 cfm Holley Dominator. The engine makes 928hp at 7,500 rpm and 694 lb-ft of torque at 6,900 rpm. Oh, and that's before the two-stage nitrous system is activated!
The first NOS Fogger system adds even more power and is activated when the transbrake is released. Yet a second nitrous system on top of that, a NOS Big Shot plate, is activated by a switch on the steering wheel. Both systems are plumbed with enough braided-steel line and anodized aluminum AN fittings to double Aeroquip's quarterly profits. The whole assembly bumps total engine output to nearly 1,400hp and requires 18 volts to properly light off the fire, which Richard accomplishes with an Optima 12-volt battery mounted in series with a smaller Optima 6-volt battery. The high-voltage goes through an MSD 7AL3 ignition box and Mallory distributor that uses a crank trigger to fire. Since the Jeep is only used for short bursts, a dinky, lightweight radiator from a Volkswagen Scirocco is sufficient to cool the engine.
From there a TH400 three-speed automatic is subjected to the punishment that the AMC engine dishes out. The transmission uses a Coan 6,200 rpm stall torque converter, an ATI manual valve body with an internal trans brake, and a 2.10 First gear. Richard built a chain-drive transfer case with two 60-pound chains from Power Pro Racing Products. The transfer case doesn't provide any gear reduction, but it is the lightest, strongest way to get the engine power to both axles. Multiple hoops surround the driveshafts as they route the power to a rear Ford 9-inch and front Dana 30. Yes, Dana 30. A wide-track axle out of a later CJ was used up front with 4.10 gears and an open carrier. The relatively small front tires and lack of contact with the ground allow the axle to live with the big engine power. Wilwood disc brakes are used at all corners to shed rotating mass and provide shorter stopping distances at the end of the track. A Flaming River Pinto steering rack also reduces weight, doesn't rob any horsepower, and eliminates bumpsteer when the front end comes up and down during hard launches.
The rear receives the brunt of the abuse, and as such the narrowed Ford 9-inch has been fitted with the best components Richard could find. These include the Moser aluminum third member with spool and 4.34 gears that accept the Moser 35-spline gun-drilled axleshafts. The taller gears in the front axle allow the Dana 30 to pull the Jeep straight when the tires touch back down to the ground.
Body and Interior
The steel body was replaced with a Power Pro fiberglass body last year in an effort to shed weight from the Jeep. The entire back of the tub is gutted to shave even more weight and make room for the cut Boggers, but the windshield frame and door hinges were retained. The windshield frame is carbon fiber and filled with a Lexan windshield, but it keeps the distinctive CJ look. The front Power Pro one-piece hood has a huge Pro Stock scoop to clear the carb and is easy to remove with Dzus fasteners when it's necessary to access the engine bay. The body was sprayed with Jeep Solar Yellow by Buster's Auto Art in South Boston, Virginia. Up front, a Moon Eyes 3.5-gallon fuel tank feeds 116-octane race fuel to the engine and adds a bit of weight to help keep the front tires on the ground. A 20-pound weight was also added to the front bumper, but Richard is constantly dialing different amounts of weight to help weight transfer depending on track and atmospheric conditions.
Inside, the aluminum panels were powdercoated with a Hammered finish and keep the mud out of the interior. The aluminum Kirkey racing seat behind the steering wheel is the only seating in the Jeep, and it fits squarely behind the Sparco steering wheel and AutoMeter gauges that monitor rpm, oil pressure, water temperature, vacuum pressure, transmission line pressure, transmission temperature, and nitrous pressure. Phew.
Good, Bad, and What It's For
Richard is still getting his Jeep dialed in since hitting a guard rail at the track earlier this season. He moved the engine forward 31/2 inches in the chassis right before we shot this feature in an effort to keep the front tires closer to the ground. Once he gets the suspension and weight-bias dialed in, he should create plenty of headaches for the Chevy-powered S10s that dominate the Mud Racers Association. "Another team told me that I couldn't make an AMC engine competitive, and I had to prove him wrong," Richard admitted.
Why I Wrote This Feature
Normally I would not do a feature on a "Jeep" that has a gutted 'glass body and a one-piece front end with no headlights, but Richard's AMC engine definitely caught my attention. I appreciate someone who doesn't shy away from a challenge, and Richard has risen more than a few eyebrows by being competitive with a lowly "underdog" AMC.
Vehicle: '77 CJ-7
Engine:499ci AMC V-8
Transfer Case: Power Pro Racing Products chain-drive
Suspension: Three-link, coilovers (front), four-link, coilovers (rear)
Axles: Dana 30 (front), Ford 9-inch (rear)
Wheels: 15x10 Weld Drag Lite (front), 15x18 Real Wheel (rear)
Tires: Sand Tires Unlimited 14.5x15 (front), cut 39.5x18.5-15 Super Swamper Bogger (rear)
Built For: In honor of Richie Dunavant