Clear up something in the original trans-am cars?

My neighbor is about 55, and he'd recently run across a guy with a "somewhat original" 68 or 9 Z28. We were talking about this and it occurred to me............

Chev created the 302/ Z28 for TA even though it was "pretty easy" for them by juggling SB Chev parts
Even so, it was a "new" created engine for that program so much as the required production vehicles

Ditto Ford, Boss 302, which really was a new engine creation, and they were also sold to the public as such

But Chrysler? CREATED NO SUCH street version of the destroked race engines. How did they "get by" with the rules of so many production numbers using the 340, instead of the destroked race engines?