Today I have an 84 Chevy G-30 Van with a 350 in for a Water Pump and Thermostat. Pretty easy job really. Except that this era of GM cars and trucks had a hodge podge of Fastners. Some are 3/8 threads with a 9/16 head. Others are a 3/8 thread but with a 15mm head and others are pure metric. Those of you that were not around when these were popular do not know what you are missing.