What's the torque curve for our cars? I had it explained to me recently by a mechanic who's into drag racing that shifting when you hit max torque gets you quicker times.

Fox

The stock torque peak is at 4800 rpms. I believe the way that you are thinking of is by shifting so that you end up on the torque peak immediately after the shift. By my experiences in my eclipse, shifting at 6k seemed as fast, maybe even faster than 7k. Just my thoughts.

No, your mechanic is wrong. Torque gets you off the line, HP is what makes your car go fast in the 1/4 mile. (Well, it's not THAT simple, but it will do for the discussion.)

If I shifted at our stock torque peak (4800 rpms) I'd run 17 sec 1/4 miles.

Knowing when to shift depends on your engine's red line, what your HORSEPOWER curve looks like, and how your gear ratios relate to each other.

It can be somewhat complex. But basically, you shift when you would get more horsepower TO THE GROUND (taking gear ratios into consideration) in the next higher gear than in the current gear you are in, OR when you hit red line, whichever comes first.

Maybe for an old V8 that made all its power at 2500 rpms and dies out at 3500 rpms, it would be ok to shift at the torque peak, but not us!

For us, it's easy. Bone stock, I'd shift at 6500-6700 in 1st, redline in 2nd gear (because 3rd gear is is a bit tall compared to 2nd gear). Once you have even any light mods (CAI and muffler), shift at redline. The car will make enough top end HP to make it worth it.