After plugging the vent hoses back in place, the Opti unit is returned to the engine. Don't worry about synchronizing the timing--it will only interface with its drive in one position. Now is a good time to replace questionable oil seals and definitely the right excuse to do the plug wires, but be warned, it's not fun. Tech tip: Accessing the plug wires on an LT1 is often easier through the wheel wells with the wheels removed. You can get a set of pre-made LT1 wires and a new coil from MSD as well.