Need help assessing this 1965 Dodge Dart 270 4-dr sedan

That looks like the water pump, not the block. Look more toward the driver's side behind the power steering pump. It'll be up at the top edge of the block, just below the head gaskets seam. It's probably painted over, so, you may have to scrape a bit of paint off to see it unless you get the light just right. If you can get it up in the air, or, if you have a real good mirror, you can see what the block casting is above the starter.