383 vs 360 in an A 68 Cuda

If you're starting from scratch the swap is viable and not too difficult if you have good mechanical skills.
I did the big block swap in the late 70's when I was 16. I've only owned big block powered Mopar cars.
That said, if I were doing it today I would install a roller 360 and never look back.
A roller 408 would be my choice since the modern Hemi swap wasn't mentioned.