Was my first new car; I got it the summer of 1970 and it was a big block killer, it would walk a 396 Camaro or Chevelle same for a 383 Roadrunner or 389 Tri Power GTO. It was a high winding package and was damn fast right from the factory. The only Ford I ran back then was a 70 Boss 302 and I beat him no problem. Got whupped by some SS 454 Chevell and a 440 Six Pack Road Runner. But run of the mill 396 or 383's were easy prey for the little 340. Never ran a 428 or 390 back then, but my guess is I would have beat the 390 and lost to the 428.
Would love to find a 70 Duster 340 some day to relive those days, but I still like my old Fords better these days. Just don't bad mouth the Mopar 340, is was one hell of a package back in the day.