Hot Rod tested a Corvette and a base Trans Am in May 1998, and the Trans Am actually put out more rear wheel horsepower, despite it being rated at 305 HP to the Corvette's 345 HP. Hot Rod concluded that GM was selling slightly overrated Corvettes and grossly underrated F-bodies.
But we have seen them do that before.
You wouldn't happen to still have that article, would you? Would be pretty cool to share it on here and keep it documented. I noticed Hot Rod's website seldom has some of those older articles maintained online. Occasionally I'll find an older gem, but not all of them are still there.
I did find this on camaroforums.com, though it would still be neat to have the actual article either linked here or scanned right from the source and upload the photos.
"'98 Pontiac Firebird Trans Am
Miles On Test Vehicle: 4,233
Engine 5.7 OHV LS1 V-8
Transmission 6M
Rated Power: 305 Hp at 5,200 rpms
335 lb-ft at 4,000 rpm
Dyno Observed Power:
292.8 Hp at 5,400 RPM
307.5 Lb-Ft At 4,400 RPM
'98 Corvette
Miles on Test Vehicle 5,237
Engine 5.7 OHV LS1 V-8
Transmission 6M
Rated Power: 345 Hp at 5,600 rpms
350 lb-ft at 4,400 rpm
Dyno Observed Power:
285.6 Hp at 5,400 RPM
301.2 lb-ft at 4,100 RPM
Winner '98 Pontiac Trans Am with 7.2 HP!
What they say: Because we tested the Pontiac Trans Am first and were duly impressed by it's near-300 Hp rear-tire reading, we expected the Corvette, with an extra 40 advertised Horsies, to deliver in the neighborhood of 320 Hp to the road. We queried tuners and members of the late-model performance aftermarket who unanimously suspect GM is installing the same 5.7L LS1 motor in Z28's, Trans Am's, and Corvettes. Yes, the intake and exhaust tracts differ somewhat, but according to these sources, not enough to account for significant performance desparities. So what we appear to have are slightly overrated Corvettes and grossly underated F-bodies. Regardless of paper-and-ink power ratings, any of these cars is capable of sub-6 second zero-60 and mid-13 second times off the showroom floor, and that's all ya really need to know.
page 46 Hot Rod Magazine May 1998."