These are the two oil pumps that are listed for a 2.3. The stock Merkur aluminum pump and the replacement Clevite M86E pump. The pump outlet passage is smaller on the Merkur. The M86E pump outlet hole is the same diameter all the way down to the gears. The Merkur pump has the restriction that you can see in the passage.

The pump pickup is in a slightly different position on the Merkur pump. The bottom plate is thicker on the stock pump. You can see signs of the gasket that was on the stock pump.

Merkur pickup.

Clevite M86E pickup.

The internal parts are the same but the finish on the surfaces is very different. The factory pump had a much smoother finish on all surfaces. This M86E has never been used and you can see wear on the plate already.