I have a 23 pitch LH aluminum prop on a 280 Volvo penta. Just purchased a brass 23 pitch LH prop. What benefits does the brass prop have over the aluminum to push my 24 P & D with a sbf pushing about 350 hp?

It really depends on the geometry. The blade form, area, cups, camber etc. may create better efficiency or top speed. Quite a bit of additional info would be needed.

Best idea is to try them and see.

Brett

They're actually bronze, not that it matters. Bronze is far more corrosion resistant. The bronze prop should flex less, possibly acting as if it had higher pitch. It should also be thinner, causing less drag.

Theoretically...

Props are typically NiBrAl, a type of bronze alloy. It is quite strong, durable, and corrosion resistant. This material is the mainstay of yacht and commercial boat props. The blade sections are not quite as thin as stainless, but should be significantly better than Aluminum.

Nibral is a nickel, bronze and aluminum alloy. It is commonly used in propeller options today.
We sell nibral CNC'd propellers from ACME to fit many specialized applications. Indeed they are a mainstay in the cruiser industry since they are more durable than aluminum and less costly than stainless.

zavier24 might actually have a brass propeller since back in the day we did make propellers out of brass. We actually have numerous brass propellers in the shop. They make great ornaments and conversation pieces.

Brett