Tech Notes
Who: Mark Wells
Where: Lino Lakes, Minnesota. Lino Lakes is in Anoka County, the fourth most populous county in Minnesota.
What: '69 Plymouth GTX
Engine: The original 440 is still in the car. Mark sent it to Performance Concepts in Forest Lake, Minnesota, for a performance rebuild. It was bored 0.030 over, decked, and paralleled, then it was reassembled with the stock forged crank and rods. Mark chose a set of forged TRW pistons that would yield a compression ratio of 10.4:1. The stock iron heads benefited from serious porting, hardened seats, and upgraded valve stem seals. Mopar Performance 2.08/1.74-inch stainless steel valves are actuated by Six Pack rocker arms. Mark went to the bottom of the page when picking his cam. He chose Mopar Performance PN 4120237, a single-pattern hydraulic cam that specs out at 292 degrees duration at 0.050-inch lift and 0.509-inch valve lift. A set of Comp Cams pushrods round out the valvetrain. Though the engine has not been run on the dyno, Mark guesses the combination is good for about 500 hp based on data from similar builds done by people he knows.
Induction: Mark's intake manifold is an Edelbrock CH4B. It's a dual-plane manifold that Mark port-matched to the cylinder heads. On top of it is a JET Performance Products Stage 3 Holley 750 carburetor, and it's fed by a Carter mechanical fuel pump. The air cleaner is a '69 Air Grabber.
Ignition: A Mallory dual-point distributor delivers the sparks to Autolite plugs. The MSD 6AL ignition controller and MSD Blaster coil ensure those sparks are hot and consistent.
Exhaust: A pair of Hooker Super Competition headers are shoehorned into the engine bay. They measure 1 7/8 inches at the primary tubes and have 3-inch collectors. Exhaust is routed through 2 1/2-inch pipes to a pair of Flowmaster two-chamber mufflers and exit in the stock location beneath the rear bumper.
Transmission: Mark built the 727 TorqueFlite with a Turbo Action valvebody, a TCS Full Metal Jacket steel-sleeved aluminum drum (that holds more clutches and is 2 pounds lighter than stock), and a 9 1/2-inch Dynamic torque converter that stalls at 3,500 rpm. He controls everything with the stock column-mounted shifter.
Rearend: The stock 8 3/4-inch rear was built with a Precision Gear 4.10:1 ring-and-pinion, Dutchman axles, and an Auburn Pro Series limited-slip differential.
Suspension: The stock GTX 0.92-inch torsion bars and 0.875-inch sway bars are up front, and Mopar Performance 3800 Super Stock springs are out back. Jounce and rebound are controlled by Competition Engineering shocks with 90/10 and 50/50 valving front to rear.
Brakes: Though Mark left the chassis and drivetrain mostly stock, he did upgrade to front disc brakes, replacing the stock 11-inch drums with 11 3/4-inch rotors from a St. Regis and calipers grabbed from an '80 Volare. The stock 11-inch rear drums are still there.
Wheels/Tires: We're suckers for big steel wheels, and Mark's GTX doesn't disappoint. He's got a set of 15x6 and 15x10 Wheel Vintiques wheels mounted with a pair of BFGoodrich 235/70R15 tires up front and Mickey Thompson 296/65R15 ET Street radials out back.
Interior: Mark redid the interior with OE reproduction materials, including reupholstering the stock seats. He sent his gauge cluster to Redline Gauge Works for cleaning and to have a reproduction tachometer added. The original AM radio and eight-track player are still present and in perfect working order. Mark had an iPod jack added to the radio receiver for when he tires of listening to talk radio and his collection of eight-track tapes.
Paint/Body: Mark did all the bodywork and prep before sending his GTX to Chris Walker in Stacy, Minnesota, who sprayed the superstraight basecoat/clearcoat using DuPont jet-black urethane and clear. Chris also did the stripes on the Air Grabber hood in the correct PPG Organosol textured coating.