Your poor running on start up could be the Idle Air Control motor is sticking a bit, it should run steady from cold. The start up and idle range mapping is not normally changed much from the standard settings. A clean out with some spray carb cleaner sometimes works.
The S&S IAC p/n 55-5085 is quite expensive if you just want to change it for diagnosis but there are plenty of cheaper alternatives, have a look for the numbers in the Alternative Parts List.
