To the OP:
NO, you cannot use it on a 383 or 400. It is too wide.
If you had a 413, 426 wedge or 440, it would and it would be better than a stock intake, regardless of others' opinions.
However, for you, the DP4B is about equivalent. Or a Performer.
Actually, there was an exhaustive 383 intake manifold test with more than 10 intakes, find it and go.
R.