Thanks for bringing this up OP.

I just pulled the FA off my newly acquired engine and found the carb to be jacked up. Seeing the cost of a new Quick Fuel carb I about crapped. The Sniper is a fair amount more, but you get a lot of other parts as well.

Now, has anybody ever installed an O2 bung in a set of KE Thunder and Lightning exhaust?

I can’t comment on the O2 sensor, but regarding cost, make sure to account for the fuel delivery system upgrades that you’ll need. The systems sold under marine do not include pumps, etc.

** I can make you a nice deal on a 850 Mighty Demon!

I found out that there are not many people who will perform custom tuning on a MEFI 3 after rebuilding my Whippled 500EFI about 5 years ago. This is what initially sparked my interest in learning how to tune EFI myself. I started out knowing nothing about EFI and there has been a learning curve. Since then I have learned how to custom tune on my own by trial and error. Also by asking the right questions when seeking advise from Whipple and other EFI tuning specialists. Now I am not scared to install and tune any EFI setup on my personal projects. What I have found through my own journey, learning how to tune EFI, is that incorrect installation is usually the culprit for 9 out of 10 Holley EFI and Sniper problems. That being said, out of the handful of Holley EFI installs I have done, there was one Sniper unit out of the box that was only spraying fuel from 3 injectors. Holley sent out a new replacement within 2 days and included a return shipping label for the defective unit.

The Holley Terminator setup clearly states in the directions it is not waterproof and to mount the ECU in a location where no moisture exists. This would eliminate any intentions for marine usage. Running an O2 sensor in a wet exhaust will shorten the lifespan of the sensor dramatically. I would expect having to replace the O2 sensor every 30-40 hours. I only use the O2 sensor when it is in self learn mode or I am custom tuning it in a wet exhaust. Once the base map has been optimized and setup properly, there is nothing wrong with having it run in open loop. My next Whipple motor will be using a dual sniper setup.

Having the O2 sensor last depends on location within the exhaust and reversion tendencies of the cam profile. I run O2 full time in wet exhaust. Current sensor has lasted 10 years.

My set up is TRS with CMI headers and tailpipes. With the wet adapter I should be able to protect the O2 sensors pretty well.

I appreciate all the comments on experiences and direction.

I’ve spoken some with SystemProEFI and they’ve given me some good insight and a parts list, but I’m still on the fence especially from a cost to benefit standpoint.

I think adding bungs to my tailpipes and Howell adapters to O2 sensors with a AFR monitoring system would work give me the best bang for the buck right now. It’ll also get me in the water quicker.

I really want the injection, but the expense is way up there. I can do it, but I’d like to put the money into other areas if possible.

FWIW, I had one of the original Quickfuel carbs before Holley bought them and it was an excellent product and very user friendly and reliable. My current boat rarely leaves the lake or ventures very far from shore so if anything went haywire it’s no big deal. If I was doing serious offshore I may prefer carbs if I couldn’t muster up for a serious injection system. Plenty of folks have great success with the Sniper running offshore, but for me that’s my opinion on the matter.

The MPI system caused me some trouble about a good fifteen miles out in the middle of now where (ended up being a bad knock sensor). When you're having issues and there's no land to be seen in any direction, it gets a little spooky. Simple is better for me right now.

Not only does fuel injection provide excellent start up and drivability when in closed loop it provides better fuel efficiency and in turn increases engine life by not washing the oil off of the bore when over fuiling. I would vote for EFI and if your worried about getting stranded do the non-lock out distributor set up and carry a spare carb.

Spot on.
EFI starts paying for itself from day one in fuel usage, too many other benefits to list again.

Now excuse me I`m going to rip the Fuel Injection off my cars and install carbs , I don`t want to get stranded with that troublesome EFI