That carcraft test doesn't prove anything.
They are to far away from the detonation limit with 260@0.050 and only 10.88:1 compression.

They are even admitting it on the second page:
"We're not going to be quite so cocky about debunking the claim that you can run higher compression on pump gas with aluminum than with iron. Our test does not definitively prove that. It may not have even tested it."

383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.