In 1965 a V-8 Mustang was one of the quicker cars from red light to red light and with a stick shift they could easily spin the wheels which gave the impression of being fast. But I had a 65 Valiant with a 1bbl slant six that could easily outrun all but a few V-8 Mustangs. The Valiant’s 0-60 time was measured on a calendar but eventually it would reach 100+ and only the rare Mustangs with the tall final drive could do that. And the OHC 6cylnder Firebird could embarrass Mustang owners in any heads up competition.
And most of the early Falcons had 144 or 177 cu in engines that had weak valve springs that seemed to have been intentionally used as a governor. The valves would float about 4000 rpms @Bing. Of course those engines used asthmatic carburetors also. The Mustange V-8 was a hot rod in comparison.