Either engine choice would definitely have a closed cooling system. Open cooling is not an option out here if you want to be on the water and not rebuilding engines each year..

Thanks for the advice Mange. I originally was going to run an SCX. In speaking with the manufacturer, I didn't like that there is no warranty and also that they require regular maintenance (bearing and gear inspection and replacement) when running moderate to big power. I have read every thread on the site about the arnesons on single setups (both V and cat). Seems like they can be very picky on what prop you are spinning and there is trial and error involved in finding the right one for the boat. As far as a #6, my short engine bay in the eagle 30 doesn't allow for moving the engine forward to fit a trans for a #6 drive.

Also, I spend a lot of time out at our sandbar here with the boat backed up to the sand to allow for passengers to easily get in and out. This has caused the demise of the bravo gimbal ring as the leg sometimes bumps the sandbar. With the arneson, I wouldn't have a "leg" hanging down as low to worry about. I am building a large swim platform that extends past the arneson drive and also running the arneson prop guard.

Just because a builder claims to be a marine engine builder means nothing not one ounce. IMO many engine builders including marine engine builders are not all of that in a nutshell. I am not refering to anyone in particular here but will add there is combo builders out there for auto and marine that some are very good. Boostpower, Paul Phaff, Reyer & Morrison build other stuff beside marine engines.

Reyer & Morrison inwhich you think drag racing only but could and would hang with any builder listed in this thread very easily without breaking a sweat thinking about it. Evan Dart could build you a very great marine set up if you wanted to throw down the cash.

I do know Boostpower, TCM, Reyer Morrison and Throttles Performance are not using Holley EFI set ups on any builds like many others because of its limitations.

I am using Throttles Performance in Fargo North Dakota area for the 665 CID build, no super charger or turbo for the build, Do not want it.

Without a doubt I have 110 % confidence that Mark at Throttles Performance can handle this without any problems, again without one doubt. We have him as well for tuning and his tuner friend. An FYI he tunes or has tuned for everything with a big name on it.

I am going full custom with all of it. Can have it built stronger and better and alot cheaper than any marine OEM plus tuned without all those OEM limitations from Merc.

Take that SC off the merc 700 SCi and you got not much, Most can add an instant 125 to 175 hp by adding a SC to the build mix but have them do it without and see where you end up.

Im going to say the opposite or everyone else....go the custom BBC route.

There are 2 guys local to me, one with 600SCi's and another with 700SCi's and both are having issues with going into guardian mode. Both of them have whipple upgrades and both have the updated water line routing done and still have issues.

Some people may have them or have had them and theyve been great, but to me, unless you keep them 100% stock then they arent reliable anymore. Any what fun is stock after a while?

I agree that the resale may be better with the blue motor, but if you think about it, after you change it to surface drive, change the engine/rigging, etc etc, how much is it really going to matter if it has a blue motor or not at that point?

Good luck, sounds like a cool toy

You Throttle's Performance ?

I recognize the 900HP forum member name from other places.

Make sure you get a really long dock pole. That should be hell around the marinas with a hugeblock. Get it pointed in the right direction and start it.

^^^^ 100 % wrong if you have a tuner who knows how to tune for all of that no problem - no matter of CID plus cammed correctly. Certain current stand alone ECM's its all possible to tune for whatever but and the but is again the tuner needs to know what in the hell they are doing plus set it up on the dyno then finalize it on the water testing with fine tuning. So many marine tuners still using MEFI 3 and 4 and a few MEFI 5's out there - such outdated, 10 to 15 years behind the times.

Boostpower is using AEM and has never looked back.

We are going to use MS3 PRO. If wanted to, we can idle the 665 at 750 rpm's. Prob 900 rpm's is most likely to have better oil flow and better water flow thru the engine.

And I agree with closed cooling hugely for marine engines no matter of CID.

Well the search is over for now! After speaking with Brett, I ended up picking up his new 700sci.

With several inter-island trips per year (open ocean navigation), reliability is #1 especially with a single engine setup. So I will sacrifice some power for this peace of mind...for now.

Appreciate everyone's input!

Congrats and keep us posted on the progress!

Large cubic inch motors require cams with a wide LSA. This really helps with idle. We have no problems getting big motors to idle under 500 Rpms in and out of gear with a carburetor. You can really turn the idle down so low the motor hardly runs. Couple that with a big arm spinning around and the motor doesn't even flinch when you drop it in gear.