Don't get sucked into the bigger carb has to be better......While a bigger carb may make a few more outright hp [ & it may NOT.....], there is something called throttle response & drivability that needs to be considered for a street driven car. That was why Chrys used the TQ carbs with small primaries; it gave great throttle response & driving feel. The big secondaries were there for the top end.....but the 340 never used the full 800 cfm capability of those carbs in stock form.
The 383 used the same 625 cfm Carter AVS as the 340. A 1969 Super Bee with a 383 ran a 14.04 1/4mile. A 428 Ford with 715cfm Holley ran the same 14.04 1/4. Both had 3.5 rear rear ends. Another 428 Ford/715 Holley ran a 1/10 th at quicker, 13.94......but it a 3.9 axle. You would expect it to be slower with a 3.5 axle like it's stable mate.......
Sooooo, you have the 383 giving away 45 cubes to the 428 Ford & getting the same 1/4 times.....with a smaller [ & better ] carb.
All the cars were in showroom stock condition....which was the purpose of the test to compare showroom stock.