Where is engine block drain plug on 1997 Chevy astro van?

on v-6 the oil filter is the drain

Dude . . . the oil pan drain plug is near the oil filter on the passenger side very close to the transmission bell housing. Removing the oil filter will drain some of the oil, sure, but if you want to empty the crankcase you will need to pull the drain plug. Check your manual for the correct torque to use when replacing the plug and don't forget to use a new gasket.

There is no drain plug for the transmission pan so this is kind of hard to screw up. Just check your fluid levels after draining the oil if you're concerned you might have emptied the wrong thing. As always, I am not a mechanic and your mileage may vary. .