Mike, if you could get your 60's into the 1.7s with those tire I would expect mid to high 11s at about 117. Getting the car out and into 2nd gear is the key to good times. ET is about traction and hp, your mph through the traps is relative to hp and weight. Trap speed is a good indicator of hp.
Wallace Racing has some good, pretty accurate, calculators to play with.http://www.wallaceracing.com/Calculators.htm
One of the problems with calculators is plugging in the hp. Flywheel and wheel hp are not the same, some calculators don't define which to use.
Also drivetrain hp consumption is a big factor to consider. A 4l80 is similar to a TH400, they both need a lot of hp to turn them. A friend is in the process of removing his TH400 and installing a TH350, expecting the car to be 2 tenths quicker. That 69 Camaro street car runs high 11s, low 12s at 112 with an old school 327, with good parts.
Get your car scaled sometime. You may be able to find a local drive on scale, here we have a scale used by the local grain supplier to weigh trucks. It was pretty accurate and check often by the state. Had my car weighed on that scale and the next day weighed on a 4 corner race scale, the difference was 15 pounds. My car is fat 3625. Also if you get to a track they will have a drive on scale, this will give you car and driver weight. The LS saves weight, the trans and rear you run adds weight compared to stock. You could be in the 3500 range less driver.