A lot of it has to do with the track conditions, and how well the track is set up. I have been to several tracks with the 340 six pak car a few years ago, and my best times(14.9) were at a track right close to home. Times varied from a 14.9 to a 15.6 from track to track. Atmosperic conditions also have something to do with it, as does tire pressure, I never lowered mine at Gateway (ran 32 psi, way too high for drag racing). We ran a consistent 13.7 with the Viper last summer at Gateway on Saturday morning, when it was wet and very humid (3 passes). I know that with a dry track, lower humidity, and lower tire pressure, the times would have been much better, that and my getting used to launching this brute. It does not launch like the 340 six pak at all! However I did cut a .517 light on my very first pass in the Viper. (Leave on the last yellow, leave on the last yellow) Not bad for a 55 year old wanna be drag racer!