I am close to getting my new Lavey 2750 with a Dustin Whipple built 509 with his 4.0 screwcharger. The bottom line is this, the engine is currently set up for 91 octane. I can get 93 with ethanol, 92 without, (which I will likely use). The dyno run on 91 made 967 hp and the run tuned for 93 made 1023 hp, both at 6400 rpm. I will probably not run at 6400 rpm, nevertheless there is about a 50 hp difference or 2 to 3 mph.

In my discussion with Dustin, we agreed that there is some margin of safety in this scenario and I can always get the MEFI4B retuned. I run 1 local poker run each year. The rest of the time I do all around boating with the family. I have torn up more outdrives and engines than I care to admit. Do you see anything here that I am missing? Again, I am looking for reliability and to keep this rig longer my normal 3 year deal. Thanks for your input.

Quent

run the best fuel you can get and keep the timing backed off a little from max. It may cost you a little speed but it will hold together longer in the end.

Quent,
Even though it was tuned on the dyno, it should be checked in the boat. I test run and check every engine that I build, whether I install it or not. It's a good pratice. Some boats will load the engine a lot differently than others. This may cause some knocking that you would never know about. It may also need some fine tuning going in and out of gear.
I install O2 bungs in the pipes and check the afr's on the first run. I also hook up the laptop and watch for knocking. I'm sure Dustin has the tune on the money, but I still think it's a good idea to verify it in the boat. Give me a call if I can help.
Eddie

Thanks, Eddie. I will try to hook up with you when I get back in country. Quent

Sounds good. Let me know how I can help.
Eddie