Wideband AFR tuning help.

Do you know for sure your getting out of the idle circuit when cruising? At moderate speeds you may still be running on the idle circuit. I see you say it's running fat up top. Remember the power valve channel restrictors (PVCR's) also come into play at WOT so you have to figure them in. It's possible to have the a/f ratio perfect in the idle circuit and main jet circuit but either fat or lean at WOT. To make sure it's the secondaries that's running rich you can wire the secondaries closed and go for a top end blast and see what the a/f ratio shows. You might be surprised to see it's really the primaries that are causing it to run rich at WOT due to PVCR's being too big. I've ran into that before even on non modified carbs. Just last week I took apart a 3310 and found it had some huge PVCR's.

BTW: 17:1 is real lean but that's what alot of the little econo boxes are running at for good fuel mileage. I personally don't like to go over 16:1 just for safety sake. As long as your not overheating or surging it's fine. 14.7:1 is stoichometric (sp) which is the supposed ideal perfect ratio for best combustion, not necessarily best for fuel mileage or power.

Definetly get the timing ironed out before you waste any time trying to tune the carb. because timing does impact a/f ratio to a degree. 12.5:1 at WOT is pretty close for best power usually but every engine is different. Just have to dyno it or run it at the track to see what it really likes.