I assume that the stock heads means unported and the race weight is 3900lbs.
Here are the two extremes IMO:

1) If you don't spend a bunch of time at the track testing, tuning, and practicing and you only go out once in the middle of the summer: 13.7 at 104.

2) If you track test, tune and practice driving, in good air: 12.70 at 110.