Oh no, not my darling Z/28!? 
I wonder what you could do with it that made it a cheat? I hope my builds aren't doing whatever it is! (well, they probably aren't, it's one of my slower cars.)
I don't have a problem with this solution. Removing the cars from the leaderboards is prudent considering they're only there for some exploit. Of course you'd have to block future times, too. I just hope they fix the problem quickly.
I think the usual method is to stuff loads of horsepower (excluding cams) while keeping a stock gearbox which, in the cars on the list at least, gives a very low top speed. Can't say I've tried though, that's just what I've heard on the grapevine as it were.
Not sure how well the block is working though. Last night, after the patch but before I saw the "Under the Hood" I took the GTA out at Infineon Indycar (D Class) and the time from that uploaded to the leaderboard. I wonder if part of that is because I was running a race gearbox? If so, the upload blocker is obviously more involved that we've been led to believe. Another pointer that this may be the case is that many people last night were reporting that their garages were taking a long time to load up first time they went in after the patch - I'm not a computer expert but I wonder if the patch was examining builds for "illegal" cars?
