Exert from the James A. Elmore's article SIX Econo-Racers, Car & Driver, Jan 1969
...all the while the Hemi was proving itself to be the toughest car on the test, it was also proving to be the most exciting. Where the Chevelle, Cobra and Cyclone CJ give the impression of being hot sedans, the Road Runner comes in from the other direction – a tamed race car. And that impression isn’t entirely wrong. Chrysler’s 426 cu. In. Hemispherical combustion chamber V-8 was never intended to quietly propel Imperials down the freeway/expressway/throughway/parkway or allow you to carry an extra lawn chair in the back of your Plymouth Fury station wagon. It was designed as a race engine, pure and simple. The whole idea was to put the hurt on Ford at Daytona because Ford was too far ahead for conventional weapons. You probably wouldn’t even be able to buy one in your Road Runner if Bill France hadn’t decided, with some prompting by Ford, that it was hardly fair to race those big motors if Chrysler wasn’t going to sell them to folks. Forget about reason, the Road Runner’s Hemi (although detuned a couple hundred horsepower so that it can pass federal exhaust emission standards) is still the same basic engine used in Grand National stock cars and super stock drag machines.
What is it like on the street? Breath-taking. The Hemi Road Runner has more pure mechanical presence than any other American automobile. Of course the Hemi is noisy, although it’s not an excessive amount of mechanical noise. After it’s warmed up, the impact-extruded pistons no longer clunk around in their bores and the solid-lifter valve gear is almost totally silent. It’s the power noise that sets the Hemi apart from the others. It has an impatient, surging idle that causes the whole car to quiver, particularly when the automatic transmission is in gear and being held against the brake. And there is that lump in the throttle. Stay on the near side of the lump and you can drive at any speed you choose up to, say, 100 mph in relative calm. Go past the lump and you open everything in the two 4-bbl. Carters. The exhaust explodes like Krakatoa and the wailing howl of surprised air being sucked into the intakes turns heads for blocks. Baby, you know you’re in the presence.
If you are on a drag strip, as we were, you discover that standing quarter-miles can be covered in the 13.5-second range at a terminal speed of just over 105 mph. That is making it for a car that weighs in at 3938 pounds.