Too much timing?

With the OP's lunati cam might need a little more.
I'd actually work the opposite way at this juncture. it's at what 20* and something rpm. right?
So now work it back down toward 14*. See where it makes the most power at idle with this carb.
Actually the first thing I'd do is find out where the idle throttle position is.
Use the initial timing to get the position in the operating range for that carb. ,020 to .040 transistion slots on an older Holley New ones maybe tighter to .020 .035 range.
Make sure the idle mix screws are providing a decent level of control.

Then start tuning by testing for best performance when slipping into gear (or place in D for an automagic)
Both early and late timing reduce maximum power an engine can make under given conditions.
Whats the max power of an engine at 550 or even 700 rpm?
Think about it (or go look it up).
It's not much.
When even a small load is placed on the engine at idle, that small load can be close to the max the engine is capable of at idle.
When an engine is engaged with an automatic transmission's pump and struggles to turn it, you know how little power that engine is making.
If you've ever had a vehicle where it could be put into first gear (manual) while it idled at like 500 rpm - that's an engine making power at idle. Not saying you're going to do that with a hot rod like this, just offering an experience for a sense of the difference.
Bottom line is idle in neutral is not a way to judge power.