""I wonder if that rich dip in your fuel curve is due to overlap of the transition circuit and the main. At 3500 the motor may be pulling decent amount of fuel thru the mains while the transition is still flowing a noticeable amount.""
- You may be right. I never thought of both circuits still pulling at the same time.

""Above that point, the transition may be flowing less and the mains more. Leaning the main jet will cause your 4K RPM to be leaner as well, and some care may be needed to balance between getting it perfect at 3.5K and having it too lean above that.""
- My chart shows that the higher up in the rpm range the richer the carb is getting:
64 jets, 2700rpms: 14.6 A/F
64 jets, 3000rpms: 14.4 A/F
64 jets, 3500rpms: 13.8 A/F
64 jets, 4000rpms: 13.6 A/F
I changed out the primary jetting last night to the 62's from the 64's. The 4000rpms A/F could use less fuel too. I also swapped out the 9.5 Hi Flow power valve to a 8.5 Standard power valve too while I had the metering block off. I want to see how rich it gets at 50/55 cruise to WOT with the standard pv in it. My standard 9.5 felt a bit too strong versus my Hi Flow 9.5, so I opted for the next lower unit of 8.5. (I know, one thing at a time. But the wideband is showing me two different issues to fix. I believe that the leaner primary jet will help out the 3500-4000rpm cruise while the standard pv will help lean out the rich spike at a cruise to WOT.)


""The main jet change will obviously lean up the WOT AFR as well.""
- I currently have 75's in the secondaries and my WOT with the 64's in the primary side did not go leaner than 13.0. I will keep an eye on the WOT AFR now with the 62's in front.

Thanks a bunch for your response. I might wait until the weekend to test it out due to our current heat wave of upper 90's.

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""However, last weekend I pulled the intake again, and confirmed I am still getting oil into the runners, so I need to resolve that before tinkering any more.""
- Is this just a gasket or is there more to the problem?