New cam and idle
Its not a stock cam right? so you can't go with the stock timing. bump up the timing and if it likes it(at idle) then you need to do some dis mods. If not, try a different carb and see what that does. do you have a carb adapter on the manifold. sometimes the wrong one can cause idle problems.
Did you degree in the cam? if not that could also be part of the lope sound. and it my not be at its designated center line. Lining up the two dots on the timing chain could still have the cam out by several degrees.