Congrats 82rude, nice classic combo. Last weekend went with this club member and myself for a 30 Km round an island full throttle water spin on calm flat water cond.
He and 3 more boating mates on his 470 Rib powered with an Etec 60 HP and 2 up on my 450 Rib powered with a 2 strokes Tohatsu 18 HP with maximized prop, both were boating side by side at around 21 knots running full throttle, his tach was not working, my 18 revving happily towards its max 5900 wot revs.
Etec 60 runs a 3 alum blade 19 pitch prop, which is over propped for that Rib and usual load, OB is badly height seated as there is some water splashe up transom, hull being an old design and much heavier compared to modern mine, his has more water drag to deal with.
Happy to know that a less HP-OB propped right for max load can match same performance of a badly propped Rib with hull issues running a 3 times more powerful OB. Ain't that sweet...
Happy Boating