Owner Bio: Mark Weymouth
Driver: Scott Tiemann
Mark Weymouth, age 41, found his 455 H.O. Trans Am in 2003. He says, "I have always believed that the 455 H.O. is the best street motor Pontiac ever made. Put it in a Trans Am and you have the best combination of handling and acceleration for the '71 model year from any manufacturer." His Trans Am had only 30,000 miles when he bought it and had few options, making it an ideal candidate for the strip. Mark owns two '68 Firebirds (a 400 four-speed and a R/A-II), a '69 R/A-III GTO, a '70 R/A-IV Judge, a '70 R/A-IV GTO, a '79 Trans Am, a '99 30th Anniversary T/A convertible, and his favorite, a '701/2 R/A-IV T/A. He has been racing for 24 years, and holds the record for the fastest Pontiac ever in PS and F.A.S.T. racing with his R/A-IV GTO. Scott Tiemann is pictured here with the T/A since he stepped up to drive it on race day.
| Strip Tuning Log |
| Run/Tuning | Launch | RPM | Shift Pt. | 60-ft. | 1/8-mile | 1/4-mile |
| 1. None | 2,000 | 5,000 | 2.07 | 8.37/87.14 | 12.85/110.05 |
| 3. None | 2,000 | 5,000 | 2.05 | 8.36/86.16 | 12.88/109.50 |
| 4. 36 psi, rear tires | 2,000 | 5,000 | 1.94 | 8.17/87.83 | 12.63/110.40 |
| Best Pass Corrected | | 12.40/112.44 |
| 6. None | 2,000 | 5,000 | 1.96 | 8.29/87.94 | 12.73/110.94 |
| 8. None | 2,000 | 5,800 | 1.97 | 8.19/87.77 | 12.65/110.42 |
| Five most important runs listed in their original order |
Run Notes: 1) Too easy on launch, no powershifts; 3) Decent launch, powershifts; 4) Best pass, good shifts; 6) Spun in second; 8) Good pass.
| Strip Specs |
| Year/Model | ’71 Trans Am |
| Race Weight With Driver | 3,753 lbs |
| Curb Weight | 3,600 lbs |
| Fuel Level When Weighed | 1/2-tank |
| Fuel | 93-octane |
| Engine | ’71 455, code-WL |
| Cubic Inches Before/After | 455/463 |
| Engine Built By | Dan Jensen and owner |
| Induction System |
| Air Cleaner | Factory functional Ram Air with K&N air filter |
| Carburetor | Quadrajet, 800-cfm, No. 7041270 |
| Primary Jets | 0.073-in |
| Primary Metering Rods | 0.043-in |
| Secondary Metering Rods | CC (0.030-in) |
| Secondary Metering Rod Hanger | L |
| Spacer Plate | None |
| Intake Manifold | Stock aluminum dual-plane |
| Fuel System |
| Pump | Stock mechanical |
| Lines | Stock 3/8-inch |
| Regulator | None |
| Heads |
| Casting | ’71 No. 197 |
| Head Porting | None |
| Flow Numbers | 209-cfm at 25-in of depression at 0.400 lift (intake) |
| Valves | 2.11/1.77-in, Manley SS race |
| Bottom End | |
| Pistons | .0.035-over Diamond NHRA stock replacement |
| Rings | Diamond, file-to-fit |
| Rods | Oliver NHRA stock replacement forged, 6.625-in length |
| Compression Ratio | 9.63:1 |
| Crankshaft | Stock cast 4.21-in stroke |
| Rotating Assembly Balanced | Yes |
| Camshaft |
| Brand | JW Racing, “068” hydraulic |
| Duration at 0.050 | 212/225-deg |
| Duration Advertised | 288/302-deg |
| Lift With Specified Rocker Arms | 0.417/0.413-in |
| Lobe Separation Angle | 112-deg |
| Installed Position | 110-deg |
| Rocker Arms | Stock stamped steel, 1.5:1 |
| Ignition |
| Distributor | Stock Delco points-type, No. 1112073 |
| Amplifier | None |
| Coil | Stock |
| Wires | 7mm Delco, date-coded |
| Spark Plugs | AC R45S |
| Total Timing | 39-deg |
| Rpm That Total Timing Is Reached | 2,400 |
| Exhaust |
| Manifolds | Stock Ram Air round-port |
| Exhaust | Pypes 2.5-in |
| Mufflers | Pypes 2.5-in |
| Crossover | Pypes X-style pipe 2.5-in |
| Drivetrain |
| Transmission | Muncie M22 |
| Clutch | Centerforce |
| Shifter | Hurst |
| Rear | Pontiac 10-bolt |
| Rear Gear Ratio | 3.73:1 |
| Posi | Auburn, clutch type |
| Axles | Stock |
| Chassis and Suspension |
| Brakes F/R | Stock disc/drum |
| Wheels F/R | Stock 15x7 Rally II |
| Tires F/R | Reproduction Firestone Wide Ovals F60-15 |
| Tire Pressure F/R | 45 psi/28 psi |
| Suspension Front |
| Springs | Stock |
| Control Arms | Stock |
| Stabilizer Bar | Stock 1.25-in |
| Shocks | 50/50 OE Replacement |
| Suspension Rear |
| Stabilizer Bar | Stock 0.875-in |
| Shocks | 50/50 OE Replacement |
| Other Features | Polygraphite bushings |
| Chassis Mods | None |
| The Rest |
| Interior Mods | None |
| Exterior Mods | None |
| Safety Mods | Driveshaft loop |
| Paint | Cameo White BC/CC |
| Launch Technique | 2,000 rpm |
| Best 1/4-mile ET/MPH Prior To Event | 12.88/108.7 |