Cam advice for more torque from 340

They checked the flatness and said they were good. Since the 1121G is .01 thinner wouldn't that have the same effect as milling the heads or block .01"?
Yes, in this case, with the open chamber heads. (With closed chamber heads, you would have to consider other factors....)

Do you think you have the coolant leakage issue resolved? That is my one nagging concern with the heads and block deck.....