That MP cam has 238 at .050 IIRC. IMO, No way it runs well at idle to get a baseline with only 10* initial timing. I'd roughly double that number to the 18-22 range and it will idle much better.

Timing first!

An anology I use, carbs are like building a house. You don't build the roof first then the walls then foundation, you start at the foundation and work up. Idle (timing/carb settings) is the foundation. If that's off, you have to make compromises in the systems after it to get the car to work right. Set foundation correctly and the other systems are much easier to tune.