I did not know this. Cool !

Those are high flow, the 4 window quick fuel powervalves. If you had the stock holley ones, with the 2 small holes, that could be why it fattened up at wot. The high flow ones move more fuel.

Of course, that depends on the power valve restriction size in the metering block. Example..

Standard pv in a dominator, the pv is the restriction. High flow pv in a 650 double pumper, the pvcr is usually the restrction.

That explains the fattening at wot. I just figured different conditions. It was completely consistent from about 1k-5400, so I'm thinking dropping the primary jets should lean it out across the spectrum, yea?

I know i have taken 10 to 15% fuel out of tables on merc mefi tunes at wot and 20+% at part throttle even after bigger cams etc, numbers started in high 10's, low 11's. I tuned a 500efi w azsm throttle body, pocket ported heads, bob m cam that i built a few years ago, 27 fountain that went from 75 ish mph to 80mph on a good day, took ton of fuel out of stock tune in midrange to get to 13. to 13.2 range cruising , guy called me up and said boat used 38 gallons of gas to make same trip he previously used 45 gallons on , was concerned it was on edge of burn fown, hes approaching 75 plus hours since build, estatic that it goes faster AND gets better mileage, mercs tunes are pig rich on older stuff, lots of room to clean up efi tunes IF you dont have a low flowing injector on motor. IF a motor has 12.2 on tail pipe o2 but 3 cylinders at 11
0 and one with bad injector at 15.0 you would see 12.2
or so and melt a piston during sustained wot, food for thought!

Ok. I took the primary jets down from 78 to 74. The bottom is still rich but at 3k it's bouncing around the 13, at 4K it leaned all the way out to almost 14, but at wot it shoots down to 12.5 or so. Another issue is I can only get a decent idle in the 11s otherwise there's a blip with the first movement of throttle. It even smells rich but I don't know how to tune that off-idle transition. I'm thinking of putting the 6.5PVs back in to fatten up cruising numbers?

Feeling dumb. I thought about that blip off idle and remembered how easy it is to miss the accelerator pump lever. Sure enough. I put the old 6,5 power valves back in and the primary jets to #76 up from #74 down from the original #78. I set the idle screws a half turn out and have it at about ~12.2 at temperature and she seems happy. Hopefully we'll get another outing or two this year.

So I'm running 13.5 at 3500-4500rpm and then back to mid 11s at wot which seems about right. But at 4K is where it likes to cruise but I'm thinking that 13.5 is lean? Richen up the secondary jets?

very lean for cruise, I think.... I run 12.-12.5 at cruise..

Cruise and 4,000 rpm in the same sentence. Boy do we boaters change the meaning of that term huh.