https://cimg1.ibsrv.net/gimg/www.off...c820aabe6f.jpg
I have a 35 straight bottom fountain with 517's and centrifugal super chargers they make around 775hp

^^^ Very nice. How do the Arnesons handle in big water?

Also, hope the OP doesn't think I hijacked the thread. Figured the questions were relative to the thread, so I asked away. Been tossing the idea around myself.

No problem I can hold it wide open all I want , I have not broken anything in the drives so far .

I am running a 38 foot Cigarette Top Gun strait bottom with notched transom. Twin supercharged roller engines around 610hp each. Props are Hering 5 Blade, 18 Diameter, 28 Pitch, 18 Rake. I am under pitched and could use Green Lighnings props. Because of not having the perfect prop, I do not know my full potential speed gain. I gained 8 mph with my current props but had to pull back the throttles because of the RPMS kept on climbing beyond 5500rpm. I pulled the throttle back when I hit 5650 rpm. If I had the perfect prop, I would think I could get at least a 12 mph gain at WOT in good choppy conditions.

https://youtu.be/Of1RY4M8VqM

Not quite a “surface drive”, maybe semi surface but I have an a imco scx-4 .25” below the bottom of my boat. Leading edge of prop blades are about 44” from the edge of the pad where the water begins to rise. Only disadvantage I’d say would be torque steer but that is fixable with a torque tab and that only applies to a single. Oh and all the money spent, time spent driving to get props, shipping props, testing props etc. lol all to be expected, first world problems.

Overall my boat feels better than it did with the drive just two inches lower, better trim, handling at all speeds. I’ve ran many different kinds of props and all seem to work good, except for a 4 blade bravo but that felt lame with the drive 4” deeper. The five blades work much better now than they did 2” deeper. If you’re serious about it you can make it work but as these other guys will tell you as well it’s a lot of effort, money, and a slippery slope.

Real good info guys! Were your speed gains with just bravo/Arneson swap, or was there some HP added too? Also, being that the motors had to be mounted a little lower, did that effect how your exhaust lines up? And one more question, being that these have a transmission, do they shift smoother in and out of gear, like a TRS?

I added wedges to my exhaust and used my existing holes . With the transmissions they shift in and out of gear a lot smoother than the bravos .