70" 340 vs 72" 340 specs please

I will add to this debate my example. '72 Duster 340 with 98,000 on the odometer ALL stock , Auto . Only changes being an aluminum intake and a small 280/480 Aliance hyd. cam small tube 1 5/8 " headers , 391 gears and skinny E70/14 tires ran a best 13.53 @ 104 and would run 13.60 @ 103/104 every time out. Yes I still ran the stock TQ with an adapter to work with the square flange manifold. This car ALL stock was a solid mid to low 14 car. Right in the middle of where the 70 and 71 cars ran. Also Demons were just about 150 lbs. heavier than Dusters or Darts (true) so that might explain some of the lazy performance of your Dad's 340 Demon. EVERY '72 340 I ever saw ran very strong. JMHO

Terry