I had to do tune ups on Chevettes and Pontiac T1000s when they were popular. This is in California where they almost all had air conditioning and quite a few had power steering. Early GM HEI systems were NOTORIOUS for burning holes in the center of the ignition rotor just under the coil button in the middle of the distributor cap, causing the spark from the coil to ground thru the distributor shaft, killing the engine. To replace the distributor rotor, you had to remove the A/C compressor, the P/S pump, and their mounting brackets. WHAT A PAIN!!!