Timing
Let's take a closer look at one of these tables (it don't matter which one at this point in time)
The X axis ie the title on top
Engine Speed (rpm) is self explanatory. However please look at the Y axis label on the left hand side
Cylinder Airmass (g).
Unlike other manufacturers who use RPM vs Load (aka Vacuum / Manifold Absolute Pressure) for their timing tables, GM uses Cylinder Airmass (g). It is important for us to acknowledge this for various reasons.
1. The stock Histograms / graphs that come out of the box from HP Tuners are useless for us in terms of tuning or troubleshooting. They will all need to be modified / corrected to reference this Cylinder Airmass parameter instead of Manifold Absolute Pressure.
2. Cylinder Airmass is a calculation that takes the MAF input as well as the VE Table input into account. This is why we calibrate the MAF and the VE Table first. If the MAF / VE Table are off, than the wrong timing will be applied to your engine as it is based on this very important Cylinder Airmass (g) computation, and you will be left chasing your tail.
And yes just as with the VE Table the timing tables can also be viewed as a three dimensional graph.