Dyno'ed My 360..it's a pig..what next?
I have to agree with Rusty, AbodyB and company. I do have a few points to add FWIW.
One key way to get Hp is to have a high revving engine. In other words, if your engine wasn't done at 4700, you'ld have much high hp numbers. That said - I had my car on a chassis dyno where somehow they got much lower curve than any of the other dynojets I've had it on, and it ran out of steam early. They made some other mistakes too, suggesting to me it was operator, not the car. Since I've driven the car/engine on the drag strip, I have a pretty good idea of how it pulls at the top - and one thing it doesn't do is drop power at the top!
Now as far as what to do. First, check the throttle to the accelerator pedal. The pedal floored needs to make the throttle fully open. If not, adjust until it does.
Tuning. Got to laugh. Same word, two different meanings. Your meaning - checking the plug gaps etc, to factory specs, is the norm in the automotive service world. In the hot roddng and racing world, it means making adjustments until it a given setup runs as good as you can get it. Your engine aint stock and you're looking for power, so this is the way people here intended it.
In that context, the AFR is showing much more than just lean. It showing a trend toward lean from mid to top. When the curve is not flat, then its probably not jetting. If you get to do it again- disconnect the secondaries. This will at least tell you whether the primaries or secondaries or both are not providing a flat AFR. I'll leave it there, since I'm not sure you want to get into carb tuning..but I think that's where the most improvement may be had.
There is some chance timing could use tuning too, but what you posted should be ballpark.