Prop upgrade

[dada73]

Does anyone have any knowledge about this prop?
Number 777026 suggests it's a Johson 21p prop.

What would be a nice prop upgrade for top speed?

Motor is a 2001 Yamaha 115C V4, boat is a Driver 560.

Boat is currently topping out a tad above 80kmh with engine revving at 5500rpm with 2 pax on board.

[dada73]

here's another picture of the prop