Remember that the track is much different than the street & it's a drivers race, but with a professional driver the best that was ever recorded on a Stock 98 LS1 car was 12.9 & I don't remember the MPH. My LS1 car did a best stock of 13.2 @ 106. Now NA my car runs 12.59 @ 113 & with the 150 shot it runs a very traction Limited 11.32 @ 124 that's spinning in every gear until 4th even with Drag Radials. I feel now with the 150 shot & the big Nitto 315's that I just put on it if my little stock 10 Bolt with 3.42's can hold the bigger sticker tires I hopefully should be scraping the top of the 10's. LS1's love the spray. My car is a 6 speed all of the 6 speed cars came with 3.42's & the aluminum drive shaft. If the car you raced is a true 3.23 car it will have the Aluminum Drive shaft & on the door sticker it should have a "GU5" Code. A lot of people with 2.73's like to claim that they have the performance rearend with the 3.23's on an auto.
LS1's got a boost in 01 & 02, with the Z06 Intake w/ no EGR, different cam, better computer settings, Z06 Clutch & Hydraulics + a few of them even got the Z06 Blocks = mine has a Z06 Block. The 01 & 02 cars dyno anywhere from 15 to 35 More RWHP than the 98 to 00 LS1 cars.
Good going, LS1's aren't dogs in anyway, so here is a big High 5 from an LS1 owner. One thing if you ran him from a roll, LS1's with auto's have a really bad flat spot around 40 or 45 mph with the auto.