All my 8th edition Mopar engine book says about the standard 383 is the cam
had a total duration of 256 degrees. And the high performance 383 had a cam
with duration of 268/283 total, with a valve lift of .450 inches. Book implies
your Cuda had the 268/283 cam.
wow, just noticed the 1962 to 1964 max wedge engines, ie the 413 and 426 Stage III,
came with a mechanical cam with 300/308 duration, and .520 inch lift! Thats some
serious cam for 1962 to 1964. But, they had compression ratio up to 13.5,
that could take advantage of that much duration. I heard one of those engines at a show once.
Serious lumpy sound! Kept thinking the engine was gonna stall!