Whats the best time for a factory stock duster 1/4 miles ??

yep-16+ seconds for a 4-speed 340 'cuda with a 3.55 SG?
Never drove one, but I'm pretty sure you'd have to work at going that slow :dontknow:
The Barracuda is IMO the pig of the A-bodies, being maybe close to 150 pounds heavier, option for option, than a Duster or early Dart. Thankfully the extra weight seems to be over the rear tires. If I take the power-steering off mine, I can get real close to 50/50....... with the battery in the trunk, and alloy heads.
Speaking of 16 second quarters;
In about 1978, I inherited a 71 Demon 318/904/3.23s. It had been my brother-in-laws car. He related to me what it it had done in the quarter, when it was nearly new (he was first owner.) IIRC, he said 15.7something @ 79something . This car had P/S and PDB, with a 7.25, and nothing else.
So 16+ for a 340/4-gear/3.55s, is almost two seconds off the mark.