Tech Notes
What: '73 Dodge Challenger
Owner: Jonathan LaPaglia
Where: Los Angeles CA, where it is warm virtually all year.
Engine: The 6.1L Hemi is a crate engine from Mopar Performance with an advertised 425 hp and 450 lb-ft of torque. It came mostly naked, so Jonathan had to source a lot of parts like accessory drives and headers for the swap. The sump from Charlie's Oil Pans in Ohio fits the original K-Member, so you can drop in either a 5.7L or 6.1L Hemi. In this case, John also had to notch the K-member to clear the A/C compressor. The engine mounts are from a company called Schumacher Creative Services that specializes in Mopar swaps. They are designed to accept Tube Technologies Inc. (TTI) headers.
Controller: The Mopar Performance controller is similar to an AEM race box, fully programmable with timing and fuel maps. You even get all the sensors and a cableoperated throttle. The 6.1L was always speed density so John didn't have to switch it from a mass airflow system. The kit comes with three base maps that include one for the 6.1L. When the time came, it fired up with no leaks and no problems, which impressed John, since he did all the fuel-system plumbing by himself. After that, he sent it out to DC Performance for fine-tuning.
Exhaust: The TTI swap headers feed a 2.5-inch system with a cross-pipe. Sounded stock to us. TTI also makes headers for A- and B-Body Hemi swaps, just in case you were getting any ideas.
Trans: The Tremec TKO600 arrived with everything Jonathan needed to swap from an automatic to a five-speed, including the clutch kit and driveshaft. Because the car was so low, the transmission tunnel had to be clearanced a bit and the headers needed to be moved up to stay off the pavement.
A/C: John used the original heater box and ordered the compressor, condenser, hoses, and all the other underhood parts from Chrysler for a 6.1L. "I couldn't bear to see the hoses, so I ran the A/C lines using hard line from Vintage Air," says Jonathan. "I had a quote to do the hard lines, but I ended up doing it myself using bits and pieces. Works great."
Accessories: The front dress is from Chrysler and is for a 6.1L. The Hydroboost (hydraulic brake booster) is pressurized by a Chevy power-steering pump that was installed back when he had the 340 with a big cam and no vacuum.
Rear: The rearend is an 83/4 with 3.91:1 gears. It's just about the only part on the car that's close to original.
Brakes: This thing stops on a dime. John used the Baer 13-inch Baer Claw Track system in the front and 12-inch Baer Claw Sport system in the rear with an e-brake option. With the old engine and cam, it wouldn't stop. With the Hydroboost, it stops. He probably doesn't need it with the smaller duration of a factory cam, but it's still there.
Suspension: When he bought the car, it was riding on the bumpstops. John added Firm Feel tube upper control arms, boxed lowers, 2-inch drop spindles, and a 1-inch sway bar in the front and a 3/4-inch sway bar in the rear. The adjustable shocks are from Koni, and he had a set of custom springs built in the rear. To get the car low, John found a spring-eye box that drops the body down over the spring for good looks without the kidney damage.
Wheels/Tires: To get the look that has become traditional, the Dodge is on American Racing Torq-Thrust IIs. It has 17x7s in the front with 225/45ZR17 Goodyear Eagle F1s and 18x10s with 6-inch backspacing in the rear on 285/35ZR18s.