SB I have not seen any. Seems easy enough to make with a little machine work.

I’ve only put about ten hours on this boat since purchasing it. I put the wideband on when I got it with unknown amount of hours on the repower so I’m probably on borrowed time. I’m gonna pay more attention to where the afr is next time out and plan on a rejet
thanks for advise guys

Plus everyone needs to keep in mind, your tailpipe reading is a AVERAGE of 4 cylinders. On my dyno I have 10 o2 sensors, their is almost always a 2+ point delta between leanest and richest, sometimes more . example: #2 at 12.0, # 4 at 10.8, # 6 at 12.2 and #8 at 14.0. So, you add them together, 49. Divide THAT by 4, average is then 12.25. So a guy leans that out slightly to clean it up, now #8 is at 14.5 at wot. This difference varys depending on type of intake, firing order of cam etc but you get the idea. I dynoed a 502 w dart320s, vic jr, qf 850, all new parts customers engine builder came up with (I only dynoed this one). Had to go up 6 to 10 sizes bigger on his qf850 to get afrs where I liked them, now, they leaned it back down 2 jet sizes in boat w marine exhaust but I saw all numbers in 12.5 to 15.0+ on dyno at wot out of the box (If I remember correctly)

I have wet joint manifolds with an o2 spacer between the riser and manifolds. I have wideband on one side and left other side open for sniper efi in future. I also have an aftermarket riser set up and water doesn’t mix till the transom,hoping it keeps moisture away from the sensor

I have EMI with +3" risers. It has one sensor on the inside of the port side riser. So 12.5 or maybe 12.7 for WOT is good.

I was surprised to find I had to put on an extender to keep it from wetting the sensor. I had a set of baffles in the exhaust to keep down the noise and I think that exacerbated the problem. Plus I LOVE low idle with loud pipes, and low idle really allows reversion more than anything else.
So 12.5 or maybe 12.7 for WOT is good.

Hmm, maybe I will look into making EMI sensor plates. I'm in forced home "confinement" from a work injury and they are overdoing the waiting due to covid 19. I'd go back at this point due to boredom.

ALSO: time to eat a little crow. When I ran the boat with plus 4 in the secondaries I had a great top end AFR, but the upper mid range stayed lean. So yesterday it was 3200 rpm or blast through to 4100 and above. I had the wife and 2 adult daughters with me. So I did the 3200 most of the time. And extra stupidly I think I left my box o jets at home.
SB do you have a couple of Holley style 76's? LOL