[Alan Roehrich]

Well, with a car that needs a ton of flash stall to get off the line good, but cannot turn a lot more RPM and make good power above that flash stall, yes, 8% is pretty good. That can be difficult with a lower HP stocker that doesn't turn a lot of RPM. If your finish line RPM is more than around 1500 RPM higher than your flash stall, and is also more than 800 RPM higher than your peak HP, it can be hard to get a converter to couple up really well.

Your finish line RPM and the MPH it should give, with your gear ratio and tire size, compared to your finish line MPH, will let you know about what your slippage is.

Of course, to do that, you are assuming the lights for the MPH clocks are set very accurately. That might be a big assumption, considering the variances you see in how well they are set of the starting line.