I could see if a guy was running a stock cam and stock flywheel that the piston would (should?) be set up to rise only as fast as that engine would allow. Rising faster than the needed would cause the velocity to slow accross the bridge resulting in a lean mixture. In a hot engine: 3.0 liter, 15 lb flywheel, hot cam, head ported properly, that could rev faster than the stock spring and damper oil could respond is where I'm thinking Hammill's recommendations make sense.
I would love to go FI but want to get the most out of these SU's first. Nostalgia you know.