Exactly.
The 1955-* poly was a reduced-cost V8 for the non-hemi brand (Plymouth), and a cheaper replacement for the high-end DeSoto and Chrysler that previously got a sidevalve L6 (237, 251, 265).

"Other engines permitted in Vintage V8 competition — which are engine families introduced in 1954 or earlier — include the Nailhead Buick, Y-Block Ford, and Packard V8."
BTW: also legal for 1954: Olds Rocket, Cadillac, Studebaker (?).
Yeah, that 1955-67 poly fits right in there.

If the start date is really 1955, this allows Chevy small block, Pontiac, Rambler, and Lincoln Y block (assuming all hemis have their own class).

Too bad they couldn't find anyone who knew something about the engine.
Ooppsss - some of the experts were right in the room. But reporters have a long tradition of "why ask, when you can just make stuff up?" (also true of all political events).

Just a guess at the cam specs:
1. short duration
2. very high accel & vel (test: the nominal and .050" durations are very close together)
3. very high ratio rockers, like 2:1
4. very small LSA, like 100