The more I look at your timeslips, the more I'm convinced the car is running about what it should with a fairly stock suspension and street tire. There may not be much more in it.
For the most part I agree with this.
Might be a relatively easy tenth or two, but with that basic overall combo....... I don’t think it has 11sec speed.
Need to find a few mph(power).
If you’re making enough power, a high 1.8x 60’ will get you solidly into the 11’s.
You’re talking about buying heads.
A 408 with decent heads and a solid cam is a slam dunk 500hp.
500hp should easily run 115+ at A body weight, unless there are major issues with the car.