Comparison 340 / 289

Since you mentioned "back in the day". I grew up street racing in Ford and Chevy country. In ANY kind of drag race, street or strip... I would gamble HEAVILY against a 340 Mopar vs a 428 CJ Ford. 428 CJ's were BAD motor scooters. 351 C Fords were excellent competition with 340 Mopars, stock...but the Mopars were like the Chevys, and had alot of fantastic performance upgrades readily available. If anyone was foolish enough to leave their hood open, I'd just look to see if the motor had been opened up, and I'd place my bets accordingly.
289s weren't "turds". 289 motors shouldn't be compared to 340s. They should be compared to 273s, and there is none. 289s whooped the 273s with little effort. Hence the abandoned D/Dart program.