Conclusion
Stroke or destroke? Which way do you go to get the best e.t.'s?
Like Michael, many Pontiac racers stroke their 400s to give them the extra displacement and torque of a 455, and the popularity of this style of engine build has multiplied, as aftermarket companies have developed stroker kits for the Pontiac hobby. Destroking a motor, on the other hand, is often chosen to lower torque while increasing top-end horsepower potential.
Michael's stroked 400/455 posted low 12s, whereas Joe's destroked 455/440 earned low 11s. To be fair, we shouldn't compare these times against each other because of the differences: Michael's weighs 3,925 pounds with driver and Joe's is at 3,345 pounds with driver; the rear-gear ratios, Michael's at 3.42 versus Joe's 4.10; not to mention the rest of the drivetrain combination. However, the approach each racer took to his build shows that both stroked and destroked motors have benefits at the track, stroking working well for a heavier race car and destroking working well for lighter racecars.
What did each driver show us?
Joe showed us that better parts do not always guarantee better performance, even if logic suggests otherwise. He was confident that his GTO's winter upgrades would have a positive effect on his e.t.'s, but they haven't yet. Nonetheless, he continued to race the GTO as if he was going for a First Place bracket trophy. His 60-foot times never varied more than 0.16, and his e.t.'s for the day were all within 0.03 of each other. In doing so, he demonstrated that his destroked GTO can be competitive as a bracket racer.
Michael showed us that previous timeslips may not be a good indicator of your Pontiac's performance this year; there may be mechanical gremlins that appear for the first time after your race car has been stored all winter. When you come out to the track for the first test and tune or race of the season, be prepared for whatever the timeslips may bring you, good or bad. Then make the most of the situation by making your tuning changes and dial-ins accordingly. In Mike's case, he determined what caused his performance loss, and that he had the skills to monitor the situation throughout the event without risking his engine's life.
Whether you plan on building a stroked 389 or 400 to increase your torque, or destroking a 455 and lightening your Pontiac to achieve a better balance of horsepower and torque, the cars and combos detailed in this Shootout will give you plenty of ideas for your project.
HPP would like to thank the management and crew at Summit Motorsports Park for their assistance in making this Shootout possible and Duke Jefferson, John Labuda, and Arnie Brewer who helped make the day go much more smoothly.