Carb will not adjust

360 wit 410 hp. Going to be a sizable cam to get 410. Post #3 nailed it. Check how much transfer slot is exposed on the pri bores at idle. I will bet it is more than 0.060"...& that would be the problem.
Engine would need a LOT of timing at idle, likely 25-45*. That will close the pri t/blades.

Read the Man Vac Experiment under 'General Discussion'.