Originally Posted by What
And on the opposite end there are the ones who firmly believe their manufacturer numbers are under-rated. This is especially prevalent amongst GM owners...because those 01' SS's were definitely puttin' out 420 hp...it wasn't advertised because they didn't want to make Corvette owners angry.
Hey now, that 305hp at the flywheel is bullshit. It's the same motor as the Vette, why would it make less hp? 420 is junk and any owner who believes it is ill-inforned and/or ignorant, but I'd say that about people who believe the 305 as well. HP-wise there really is no difference between the Z28s and SSs, and most SS owners will acknowledge that.
Look at dynos and time slips of LS1 Z28s/SSs and those of same-era Mustang GTs, which really do make about 305hp. Or try an online hp calculator. They're not very accurate, but enough to tell you that the LS1s are making more than what GM states.