The Meziere would be an electric water circ pump correct ?

Desert - that's really well thought out - the whole package actually. Who did the tails?

BUP, They make both. I used a belt driven pump, they also sell reverse rotation if your running a serp setup.

Liquid, Thanks! I put a lot of work into the set up and harness. CMI built the tails for me off of PVC mockups. I have a 4" long piece of hose that connects directly to my transom mounted tips. Since my tips are below the water line this was the closest I could get with dry exhaust. The upside is its quiet at idle. My engine didn't like to idle at all with a dominator and exhaust back pressure from the tips underwater. The EFI made a drastic change in idle quality, its as good as the stock 496 now.

The Holley 60-2 wheel and trigger kit comes with a nice billet sensor mount, but some belt setups use the mounting points so custom brackets may be needed. It looks like MER's build used an aftermarket low alternator mounting bracket so he redesigned the Holley sensor mount to work. Moving to a crank trigger gives you very accurate and stable ignition timing since it takes timing chain slack, cam flex and distributor gear back lash out of the equation. Alex and Bob helped me with all of this.

Can you run this engine under a load @ 13.5:1......If so what compression ratio??? And your quench what are you running at??

No, but that's what's great about efi. You can put it where ever your comfortable in running. I run 13.5 all the way up through my light cruise speed ~3500rpm and then start to richen to 12.8 at WOT. My compression is 10.5:1, the orange motor is just over 10:1. Both have cams to run at 6400rpm.

Sounds like a very solid setup. How would you rate the overall difficulty on the setup?

12.8 at wot is fantastic in my book..i could hardly believe 13.5:1 Good luck nice when it all comes together makes for a short day.

The EFI is pretty much plug and play if your intake has injector bosses. If not, places like Wilson can add the bungs and stanchions. They did the EFI conversion on my Victor intake. Marine Kinetics handled the runner lengthening and porting.

The big advantage of this ECU is that once you load a base tune, it will correct to your commanded AFR. If you've ever sat on the floor of a boat and tuned MEFI you will appreciate the hours it saves! I'm not discounting MEFI's they are great systems. Just not as user friendly.

The ignition can stay very simple with a Merc efi distributor and single coil or you can move to DIS with cam sync & coil packs or somewhere in between. A cam signal is only needed if you want to run sequential fueling. The DIS isn't bad if your using the Holley wheel and kit. It can get a little more involved if your using different brands of crank triggers, coils or cam position sensors. If your comfortable reading a schematic it will go smoothly. There is also Holley Tech support, they are very helpful with software settings and pin out questions.

Great thread! A welcome change of pace around here. Some people take this hobby WAY too seriously lol. It's suppose to be fun, so thanks Rage for posting your success stories using Holley EFI!