Lean pop off idle?

Too easy;
the advertised duration of that cam is way too big, for what you are trying to do. At idle your cylinder-pressure is gonna be really low. That engine is gonna want a lotta Idle-timing.
And your transfer slots need to be exposed to a lil taller than wide. Forget what anyone told you. You will know that the transfers are about right, when you can run the mixture screws in or near the center of their range. If the idle-speed is too fast, retard the timing.
But this combination of tall Transfer slots and mega Idle-Timing is gonna make the Idle-speed too high. I can see this combo may require the Vacuum-Advance can be connected to manifold vacuum, and the Base timing set with it engaged.
Forget using the manifold-vacuum for tuning the idle.

But here is the really big deal; Your accelerator pump has to pump fuel at the slightest throttle movement, and that means at a gentle tip-in. To do that, fuel has to be in the pumpwell, right to the top, and the lil check-valve has to be holding it back, so that when the fuel comes thru the shooters, it is blasting off the boosters; No dribbling allowed; you need a fine spray.

I highly recommend a compression test.
I don't like that cam one bit.