IMO, What you experienced is normal.
At Idle, the engine wants far more timing than we can ever give it. By 2000 no load she could be wanting mid to high 40s an mine likes up to 60 by 2240.
But you cannot, at idle give her what she wants because, to keep the idle speed down with a typical carb, the butterflies want to dip under the transfer slots. So in response you have to increase fueling from another source, like the mixture screws. So then, you can make it idle on the ragged edge of having the transfer slots very nearly closed. When you do this, the transfers start pulling massive amounts of air around the butterflies, and the fuel flow drops way down. But you can make it idle because the timing has put the max cylinder pressure to the crank at the right time so that it really does not take much fuel to keep her running. So far everything is fine.
The problem s come when you try to drive away.
First, when you put it into gear, the sudden load pills the rpm down, and airspeed down, and now there is just barely or maybe not enough fuel ,to sustain running.
So, you fudge around with it and luck into a setting where it doesn't stall, and then you think you are ready to drive away, but the instant you open the throttle, you get this huge stumble, while the transfers try to wake up. But you finally get thru it, and now the thing is pig-rich cuz the mixture screws are maxed out. So no, with a carburator, you cannot run 40* of idle timing.
At Idle, timing is dictated by;
the synchronization of,
the stumble-free, drive-away point, on the transfers, and the chosen idle speed.
You first set your mixture screws in the middle of their adjustment range. Then you open the butterflies to a point that exposes the transfer slots underneath them to an amount that eliminates the off-idle stumble, which usually makes them appear to be square to a lil taller than wide. Then you adjust the idle-speed with timing to whatever you want it to be.
Then you verify that the off-idle tip-in, still works without a hesitation.
As the cam gets bigger, they want more idle-air than the butterflies can give at this setting, so your job is to find it elsewhere. And when you do, the idle speed will have to be adjusted by changing the timing. Eventually, your mechanical Idle-timing will likely stabilize at 12 to 18degrees. Now your Vcan will work. Yes it will.
I have,in the past, run a 223/110 cam and currently run a 230/110 cam, both on ported Vcan, both with a 22*maximum. And both with 14* initial.
BTW, you cannot hurt your engine with 40* of idle-timing, if that is what it took to peak the rpm.Run it up to 2000, and again tug on the D until the rpm peaks, then read the timing at 2000. Do same at 3000.
The engine is telling you, by the rise in rpm, that it is liking the timing increases. When it slows down, your engine is telling you that,it is no longer liking it.
But
You just can't put much of a load on the engine at these numbers, for fear of detonation.
