383 vs 360 in an A 68 Cuda
I'm still in the process of doing my 318 to 400/500 swap so I can't speak much of real experience yet.
I have however read many stories of people pulling their small block strokers and going big block, not so many swapping big to small. Leads me to believe the big block once in and done is the superior build. Do it once and right for what you desire the first time!!