Guillermo Chavez began work on the '66 Chevelle at Gear Vendors' headquarters in El Cajon, CA. There we placed the Chevelle on the racks for an easier install. The first order of business was to measure the angle of the differential and driveshaft. The differential came in at 4.5 degrees and the driveshaft sat at 1.2 degrees. It's important to check this because if the angle is too extreme it could cause unwanted driveline vibration.