Some of the early FE dry-sumps I've seen (factory XE and Holman/Moody)
used an internal dual pickup
oil pump similar (but bigger) to the stock pump. The
oil was scavenged out of the pan and deposited into an
oil tank. I believe the purpose was for adding a larger oil supply without making the oil pan larger.
The later Boss 429 Nascar motors used externally mounted, cog-belt driven oil/scavenge pump.