Replace twin I/Os with outboards?
 

Anybody ever do this?

Any lessons?

I/O to outboard
 

I did a conversion last year ,I have a Scarab 31 Viper ,that had twin mercruiser 454 magnums with bravo 1,s , the boat now has 2 x Mercury 225 EFI,s outboards on a 20 inch stainless marine bracket with swimplatform, the boat is doing 62 mph now ,and although I never tried the boat with the twin 454 ,s by reading posts from other owners ,they claim 65-67 mph , so overall it isn,t that bad for only 450 hp at the props .
The boat accelerated very good ,and pretty good on fuel too.

got any pics? how much did it cost? Thanks

Many years ago I helped take a 1983 Formula 302 SR-1 with TRS and 370hp 454s and install 250 Yamaha 2-strokes. We cut the transom and made an outboard well. The boat exceeded all our expectations. Ran great, had perfect balance and attack angle, got exceptional fuel efficiency.

We were first going to make it a bracket boat, but decided to mount the engines directly on the transom. 61 MPH on the GPS with 3/4 fuel, full water and 4 full-size people. I still think we could have raised the engines another inch or so. We sold the engines and are considering bigger engines in the future. I'll try to find some pics if you're interested. The hull is in Rhode Island in storage for now.

It is kind of amazing how well they seem to work. A while back I had a 26 Cruisers Inc. that was offered with inboards, I/Os, and OMC Sea Drives (235 hp). All the engines had about the same horsepower and I eventually met owners with the same boat in both the inboards and I/Os when I had my Sea Drive boat. All 3 boats got almost the same fuel economy (old school 2 stroke outboards), but top speed on the Inboard boat was 36, I/O 40, mine ran 55 with a light load.