I've raced a few stock ls1's and I have almost the exact same set up as you, I beat all of them till about 85 then it gets ugly for me, but I got on them pretty good till then.

 

Drag Radials. With 3.73's you will potentially be more traction challenged than he will be with stock gears. A higher stall converter will allow you a better launch but it will hurt your ability to hook up. The LS1 will probably still trap higher than you so traction at the launch, and starting time reaction will likely determine the outcome. You appear, on paper, to have a low to mid 13 second ride. I would expect 13.3-13.5 depending on many factors, probably around 102-103...

He will probably run 13.3-13.5 at around 103-106, again depending on many factors.

Let me put it this way.... If you cut a .520 light or better and have a sub 2.0 sixty foot time, you will probably get to the finish line first. Whether or not he has a quicker ET will not matter because it won't be that much quicker in any case based on your description.