Mid-Year Dyno Day
  Owner Year Cu. In. HP TQ RPM HP @
Flywhl.
Gross
Score *
1 Walt Bacon '67 468 385 430 5,600 454 815
2 Don Parker '66 427 292 368 4,700 345 660
3 Dean Pallas '65 350 317 330 5,700 374 647
4 Paul Lee '67 427 293 347 5,400 346 640
5 Bob & Jan Marie Kirby '66 427 291 344 5,500 343 635
6 Rich Caton '67 427 271 360 4,500 320 631
7 Mark Marabella '65 396 300 324 5,800 354 624
8 Paul Kerper '67 427 266 332 5,200 314 598
9 Dan DeBroux '67 383 253 309 4,900 299 562
10 Jerry Mandich '65 350 241 284 5,200 284 525
11 Brian Pallas '64 327 236 265 5,600 278 501
12 Jim Nielsen '66 327 228 271 5,200 269 499
13 Walt Koshko '67 327 217 265 5,000 256 482
14 Hugh Sanders '63 327 188 232 4,500 222 420
15 Gail Marlin '65 327 120 180 4,000 142 300
Other Corvettes
  Owner Year Cu. In. Est. HP HP TQ HP @
RPM
Gross
Flywhl.
Score *
1 Bob Radke, ZR-1 '91 350 385 372 345 6,900 439 717
2 Laura Lee, Z06 '01 385 405 340 335 6,100 401 675
3 Clarke Latimer, 40th Ann. '93 350 300 240 280 5,700 283 520
4 Paul Gibson, Fuel Injection '60 283 315 203 250 4,400 240 453

Legend: HP = Rear-Wheel Horsepower
TQ = Rear-Wheel Torque
RPM = Peak Horsepower @ RPM
HP @ Flywhl. = calculated horsepower at flywheel
*Gross Score = total of horsepower (HP) and Torque (TQ)

Like an engine dynamometer, a chassis dynamometer measures rear-wheel torque and horsepower and is calculated by the dyno software. Translating the columns, after displacement comes rear-wheel horsepower (HP) and torque (TQ). The engine horsepower rpm peak is identified in RPM. Finally, the Gross Score is the rear-wheel horsepower and torque added together.

Note that the chart includes a horsepower at the flywheel column (HP @ at Flywhl). The dyno software calculates a default 18 percent power loss from the flywheel through the drivetrain, to the rear wheels. Notice too that the flywheel horsepower ratings don't match any of the factory rating numbers. For example, Brian Pallas' '64 Corvette, with an L76 327, was factory rated at 365 hp. As you will see, the true way to measure drivetrain power loss is to dyno your engine on an engine dyno. Install it in your Corvette, then run it on the chassis dyno. Subtract the numbers, and you've got your drivetrain power-loss percentage.

We thought the horsepower figures noted in our chart would be quite revealing. Like those bench-racing sessions where owners claim 11-second quarter-mile elapsed times, factory horsepower ratings are far from real-world figures. But with a little bit of tuning, those outlandish factory ratings can be achieved and beaten by simple hot rodders' technology. Happy Dyno Day to you.