My '97 454 for reference. Your '89 may or may not be similar. I'm too lazy to open the service manual and look.
Driver's side, iron/steel block drain plug replaced with brass draincock just ahead of the oil-filter area. Knock sensor in blind hole just ahead of block draincock.
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Passenger side. Block drain plug replaced with elbow and draincock, just in front of starter and knock sensor, and behind block heater.
The perspective in this photo is goofy. Makes it look like the draincock is pointing "up", when in fact the block is angled, the draincock is almost exactly horizontal.
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