High speed powerful light diesels have only really been around for 30 years. Back in the 60's everything was natural. I remember a 1968 vintage sportfish that I was on that had state of the art in 1968 V8 na Cummins. Massive na diesels that made all of 300hp each. When the boat was re powered by modern Cummins B series, the new engines were so light they had to add tankage to get her to sit right.
The new I6's look so small in place of those old V8's but put a couple hundred more hp then the old ones.
I don't know how much one of those Packard V12's would weigh, but I bet HP to weight would be similer to a 12V71TI.