High idle. 1979 Pontiac Sunbird 305 V8

I am dealing with a 1979 Pontiac Sunbird 305 with a Rochester 210 Carb. It is idling at 2900 fast idle and 2000 slow idle. The choke is working. I cant find a vacuum leak. I hooked up a vacuum guage expecting to find something, but it pulls 19.5 inches of vac. When adjusting the curb idle screw to reduce the idle, the car starts to run rough and eventually, at a bout 1,000 rpms the car starts wanting to die. I hooked up a timing light just to see what i was dealing with and I am fairly confident that i hooked it up to cylinder one(bottom right if you are standing in front of the bay). the timing mark is visible on the left side of the motor, but not the right.. The car sounds fine, drives fine... the motor just wants to run away from you when idling.

I am currently replacing a gunky EGR valve, but i do not expect that to solve the idle issue.

I have very little experience with carbureted motors, and a limited understanding of classic cars and small blocks.

Any help would be appreciated.