They does that so's ya don't get in trouble.
I bought a 1967 Cougar in January of 1971.
289, 2bbl, auto.
Heck, a 6-cylinder Falon was faster almost.
Three year old car, basically, factory throttle adjustment gave 1/2 throtle opening.
Had to thread the rod further to get it, and man, was that thing fast after that.