The fastest I've gone in my Camaro was back in February of this year when I raced an LT1. I hit 150mph and my car still had juice in her to go further. I'd estimate about 155-160mph is what my car could do right now especially considering alot more has been done to my car since February. Back in 1988, GM tested the 350 IROC against the Foxbody 5.0 and got 149mph out of it while the Foxbody was at 146mph or something to the affect. Not a big difference in speed between the 2 really.