If you are talking about a cabin noise comparison, I've not seen it. With noise-canceling headsets, it's a bit of a moot point! I couldn't help myself.
A document establishes various noise levels produced by different aircraft, AC 36-1H. It lists the 337H, and P337H yet shows them having the same engine, the TSIO-360-G. The AC does record the RPM at which the noise was measured; 2600 RPM for the 337, but not at the MAX RPM of 2800.
The AC was published on 11/15/01, twenty years after the end of the 337s production, so I suspect there is no specific information other than this. Here is a data chart for some other Cessna's and the Seneca.
