You can buy a stainless 02 bung from places like Summit or Jeg's pretty cheap. They are easy to weld in when you can get to both sides.

GPM: Thanks for the tip, I'll look into it. I figured I could use a shorty tip on my TIG torch near the entrance to the pipe and have pretty easy access for welding.

There is a much easier way to weld in the O2 bung. This was explained to me by Eddie Young and you don't have to get to the inside. Works great. Using a step drill, drill through the pipe leaving the outside hole slightly larger than the inside hole. Take a ball peen hammer, center on outside hole and hit it with another hammer, rolling the metal down to the inside tube. Weld the inside and outside together, then sit the bung on top of hole and weld in place.

Snapmorgan: Sounds like it will save a ton of time, and be a whole lot easier than trying to TIG inside the tube. THANKS. Sometimes the best solutions are the easiest.

Either way, as long as it's sealed will work.

I DO HAVE A EZEFI ON MY 572 . ITS BEEN A PAIN IN THE ASS.. BUT ILL MAKE IT EASY FOR YOU .
my troubles will be your easy route to succsess with it .
# 1 the ezi system is very far different from XFI and mpi . the other is the o2 HAS to be 12 inches from the exhaust outlet and 8 min of 6'' from the manifold or header collector . also ! the system HAS TO BE RUN DRY . water dumping into the exhaust with all the fancy collors and crap wont work .
It will falseify the reading's of oxygen as fresh water will cool and and make the o2 read more oxygen in the exhaust and make it run fat . Hense the distance of the o2 sensors from outlet and inlet of the o2 .
# 2 if that o2 sensor gets wet in any way . SEEYA ! YOUR STUCK DEAD IN THE WATER ! AS THE COMPUTER WILL DUMP ****LOADS OF FUEL IN THE MOTOR AND FILE OUT THE PLUGS IN ABOUT 4-6 MINS, due the the fryed O2 . this is not a educated guess either !!
# 3 the o2 will not work until the water temp reads 160 degrees ... sorry but unless you have a close loop water system (airboat , trawler ,etc) your once again SCREWED .. BUT JUST WAIT , THERES A EASY SOLUTION .
since boat engines only reach up to 120 and normal is around 80-100 . you just need to simply add a resistor to the line . @ 160 degrees the ohn reading is 433. I used a 350 ohm resistor . and solved the issue. it takes a few mins to warm up before pulling away from the dock . but if your concerned with choke at cold temp then just simply hook a relay and toggle to it ..

ALL THIS SOUNDS EASY , BUT ITS BEEN MONTHS OF DEALINGS WITH IT .IT FINALLY WORKS CORRECTLY . AND WORKS LIKE A DREAM .LOVING IT NOW ... TAKE THE ADVICE I GIVE YOU !
TRUST ME IM ON FIRST NAME BASSES WITH ALL THE TECHS AND ENGINEERS AT FAST LOL ..
ANY QUESTIONS HIT ME UP .. THANKS POWERPLAY JOHN ..

1. DRY EXHAUST
2. A 350OHM RESISTOR FOR TEMP SENSOR :)
3. GOOD TO GO ......

I don't believe this is true with the newer heated style O2 sensors. Mine is up and running in about 8 seconds regardless of temperature. I use the spacer with my setup.

This FAST EZ efi fuel tuning system is obviously an automotive type system and when its applied to a marine engine, the setup, configuration and dial in seems a lot more complicated and involved than many boaters might have been previously thinking. I would think FAST should for the moderate cost of this system try slight reconfiguring and equipping so that it can be more easily adapted to existing marine performance engines. There will be problems of setting up all dry exhaust and certain distance spacings for O2's in may marine exhaust systems and this is going to be a major hurdle and problem for many hopeful users to get passed. What does FAST say about this and are they really advertising and selling this as a marine system?
Sounds like this so-called Easy system needs a bit more tweaking on FAST's part?

Best Regards,
Ray @ Raylar

I talked to FAST, and they say "no problem" using it on a boat. I asked about water temp, as I run 160 degree stats, and usually stay about 150 - 160 unless really pushing it. They said that in reality, the system starts learning around 140 degrees. I also asked about a water logged O2 sensor. They said that it would revert to the standard fueling tables in "limp home" mode.
If all else failes, I will just go back to the carbs I guess.

Haxbyspeed here on OSO seems to have had some good expierence with this Fast-EZ system I believe. You might ask him about these isssues with setups and O2's.

Best Regards,
Ray @ Raylar