383 rebuild - kinda whimpy on the dyno?

fishmens67 said
as it is now, the op's engine is done by 5300

I don't think you can say that as it wasn't tested past that RPM.

...unless there are other factors.

I've had relatively mild 318', 360's and a moderate 383 that were good to at least 5500 if not 5800. All with stock heads.