Measure the battery terminal voltage when it's loaded- - - -have someone step on the start pedal and hold it down while you test for voltage AT THE BATTERY POSTS- - - - -not the terminal clamps. A voltage reding near zero indicates a bad battery. Little or no drop in voltage with the starter switch engaged indicates an open circuit. Clean and test every connection- - - -hot and ground- - - -until you find the dirty one. Any non-loaded circuit will show full battery voltage- - - -even with poor connections. The only reason for those short braided ground straps was Chevy's "baby chicken" business model- - - - -"CHEEP- - - -CHEEP- - - -CHEEP!" They didn't cost as much as a heavy cable from the battery to the engine block on hundreds of thousands of vehicles. It's also possible to get enough paint on the starter housing to keep it from grounding to the end bell where the gear drive is located.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!