Diagram of pulley system on 65 Pontiac 400 motor?

There was no factory produced 400 Pontiac in 1965. The 400 was produced from 1967-1978. In 1965 Pontiac's V8s were the 326,389,421. Belt pulleys varied depending on if the car had power steering and/or air conditioning. Best to buy a factory service manual for the year, make, and model of your car. They can usually be found on ebay, or you could get a chilton or haynes manual from an auto parts store. Belt routing in the 1960's was simple, one groove for each accessory and the Power Steering and alternator both ran the water pump pulley as well.