I'm not sure if either duo prop drive is made for 550 HP. The DP drive is much more hydrodynamic than the Mercruiser BIII. Stock 454 is 330 HP in 1991.
From Mercruiser BIII literature from our boat.
Quote:
Single or twin applications up to 65 mph for gas engines up to 525 hp
Then there is this from Mercruiser spec table:
Quote:
Bravo 3 Maximum Power Capacity 400 HP (295 kW)
Bravo 3X Maximum Power Capacity 450 HP (332 KW)
I suppose it can be done, but not worth it in my book for that hull and age of boat.
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One of 4 Previous (Sold) Boats:2000 Four Winns 268 VistaCurrent Boat: 2004 Chaparral
235 ssi cuddy