Where to start... It was a general statement why I would pick a 383 over a 360 having daily driven Factory A-Bodies with a 383 and a 340. The "seems to be a long-standing, common knowledge in a Mopar world" is actually a long standing common misconception. As for the extra weight it really seems to be a non issue. What is the weight difference between a 7/8 torsion bar and a 15/16 torsion bar? Same for the 7/8 vs 15/16 front sway bar. Everything else is the same, only the engine weighs more. My early 68 Formula S does not have A/C or power steering and was a pleasure to drive with no handling issues. The extra weight of a 383 is easily offset by the intake flow of the heads. Maybe 190 cfm for the 360 vs 230 cfm for a 383. At 2 x intake airflow = hp that is 80 hp. 360 torque runs about 360 ft lb vs 425 ft lb for the 383. Have you heard the exhaust sound from a healthy 383, even through factory A-Body exhaust manifolds?
As for the 383 being a dog, just ask anyone who owned a 68-71 Road Runner. I worked with a guy who had a "68" 4 speed Road Runner, he had it for years. It was stock and would occasionally break into the 12's at 75-80 Drag Strip in MD. All he did was mill the heads, richen up the metering rods in the carb, add headers, gears and slicks. He never even changed the cam. It did not stop pulling at 4,000 to 4,500 rpm. Oh and yes, that was his baby. He probably tuned it for years to get it to that level. The 383 in my 68 Barracuda ran 906 heads, a Comp Cams 268 high energy cam, stock red HP valve springs, a 400 HP TQ, 3.23 sure grip, and a stock 727 5.0 kick down arm and a 340 torque convertor would spin the rear tires and move the rear sideways a foot or two before it straightened up at the 1st to 2nd shift. It also would get 16-18 mpg steady highway cruising in the midwest, up hill or down hill. Just because you would not, or could not, get any performance from your 383, does not mean someone else could not. It is not hard.
As for other engines they are not relevant in this thread.