To be clear, the first shot above is my attempt to run a three-belt big block A/C configuration, as discussed here. It did NOT work for me, belt slipped. Second shot is the same motor running the factory designed 4-belt config, no more slippage.
Here are some more pics of my other big-block A/C installation, better angles.
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Goodyear belts were sourced from O'Reilly's, they are cogged belt design but was not enough to stop slippage when the PS pump and water pump were on the same belt.