The second car was a '70 Buick GS with a 455 equipped with a 210/218-degree duration (0.050-inch) hydraulic flat-tappet cam. The drivetrain was a Muncie four-speed and a 12-bolt with 2.73 gears.
When the testing was done, the average horsepower loss for the Comet was 36.4 percent! For the manual-equipped Buick, the loss was 18.43 percent. As Jeff wrote, "The biggest culprit in this power-loss chain is the automatic transmission." Remember, a TH400 takes more power to turn than a Powerglide or a TH350 trans.
Surprisingly, one of the biggest power drains was the engine fan. One example was a five-blade, fixed fan on a 380hp small-block. In engine dyno tests, it ate 15 hp at 5,400 rpm. If your Corvette doesn't have to be NCRS judging correct, you might want to consider utilizing a clutch or electric-fan setup instead of a fixed blade.
American Mid-Year SocietyRecently, the American Mid-Year Society (AMYS) Corvette Club held a dyno test event. Founder Brian Pallas purchased his first Corvette, a '64, after his brother got one of the same year. Not unlike other owners, he started fixing and restoring his car and, in turn, meeting Corvette people.
Because of the wide C1 to C5 model diversity, Pallas decided to focus the AMYS on '63-'67 mid-years. Starting two years ago, he attracted members by inviting one owner at a time to join him at a local caf. Pallas told them that they weren't the member, their car was. Word soon spread, and there are currently over 200 cars in AMYS. There are no dues, no meetings (other than regularly scheduled gatherings), and the Corvettes don't have to be NCRS quality. Ultimately, Pallas hopes AMYS will become an international society for mid-years. Future plans include charitable events and an online store to raise funds for philanthropic endeavors.