The tune wont be able to adjust your timing. Youll have to buy a T/A or put a chip in and do away with your speedcal. If you went with a chip, a dyno could be worth your money. You would be able to tweek your a/f with the o/r pipe, and get your timing set to its optimum setting.
If you just want to do it, it will vary by time and the amount of pulls it takes to get your tune where you want it.