There is a lot of great info in these threads on EFI, thanks to Alex for taking the time to share his insight on things.
I just finished my first efi project and got a lot or answers just by reading thru. One question I have is why do some of you
dyno your motors without your marine headers and cooling? These two things will change your final tune and hp and torque numbers.

Most dyno setups are setup for closed pressurized cooling ... And they can't supply enough water or have previsions to dump the water .... The HP numbers might be different but the tune will be adjusted by the efi ..

When I ran mine I pulled water from the dyno tank with a 1 1/4 in. hose to my raw water pump water was exited out the exhaust, we just bypassed the dyno mufflers. by doing this we were able to keep engine temps the same as in the boat. I don't run a o2 sensor in the boat so it would have no way of tuning it.

http://youtu.be/-uqp_4im6b0 [ATTACH=CONFIG]522776[/ATTACH][ATTACH=CONFIG]522777[/ATTACH]
Just finished this last week. Rigging with install on way at time.

Bore 4.030
Stroke 3.750
Rods 6.000 H beam
CR 9.9
Profiler Heads
Marine Kinetics Hydraulic Roller
MSD Distributor & Coil
36# Injectors
Holley Stealth Tunnel Ram HP ECU
CMI Etops with full tails.
Stock fuel pump (black box cool fuel)

This was a fun build, the base calibration was downloaded from the Holley Global Folder. Changes were made on the base spark and fuel tables. Base timing set, and TPS set. Start-up was clean and changes made to start-up enrichment.
It took a little work managing brackets and mounting. Also had to weld in bosses to clock the thermostat housing properly. ECU harness was easily opened up and adjusted to engine for a neat appearance.

Nice #'s Brian. What size carb was on prior and throttle body/induction with EFI?
I'm considering EFI in the next year or so.

Pro Systems 1150 3 circuit Dominators

Starboard engine hit the 800 mark on its 3rd pull and we are calling it done......2nd pull was a biooootch.

That's a sweet package. 525efi power and a lot less weight!

Simply amazing job Mark!

What's missing is an after picture.

[ATTACH=CONFIG]523588[/ATTACH][ATTACH=CONFIG]523589[/ATTACH]