Where should I start?

Ok,
Just in case you missed it, just to squeak into the 12s with SuperStock type suspension and an auto trans,requires a P/W of .085.

What that means is; if your stock engine makes 245hp it's factory fresh rating, your raceweight will need to be 245/.085=2882 pounds, And raceweight is total weight at the start-line.
If the raceweight is more like 3650, then the power will need to be 3650x.085=310hp. Remember this is with SuperStock type suspension, which includes optimum gearing and quick 60ft.
But if you can't get the 60ft down, or you are running street gears, or you just can't make it hook, then the .085 no longer applies.
If your car is a half second slow ET for it's mph,Then you are traction/suspension deficient, and will need to fix that, or add more power. You may end up needing a P/W of .095 which is; 3650x.095=347 hp; just to squeak into the 12s. But if you are a bit on the mature side like me, and your car scales at 3800 on the line, well now you will be looking for 3800x.095=361hp
It should be fairly obvious that your stock 360 long block is not going to put out 347 to 361 hp with bolt-ons,and still be streetable,unless some form of power-adder is installed.
Just in case you missed it.