This motivated Tremec to create a simple driveline angle finder program that anyone could use. The idea is to measure the angle of the engine and transmission, the driveshaft, and the pinion angle ...

Use This Simple Trick to Measure an Angle Using Only a Level It's all about the plumb.

When measuring angles: it is always the angle between the ray and the normal that is measured, a protractor is used. Remember to use a ruler and a sharp pencil.