84 5.0 has weird idle problems

[5.0 Fiend]

I got my intake manifold all put back together, and it doesnt leak, but now my car is being one stubborn pony. I have a holley 750 carb, and my problem is that when you start the car after it sits for a while, it will start right up and idle at about 1500 rpms, but then it will go to 2000 rpms, then down to about 1000 rpms, then after a while it will go down to about 100rpms,not 1000, 100, and you have to stay on the gas or it will stall. After I take it for a small drive, and I shut it off, it has a hard time starting up again, it sounds like it has low juice, (new battery), and it is turning over very low, but if you keep pumping the gas and keep your fingers crossed, it may just fire up. Now my questions are, could incorrect ignition timing do this? (I took my distributor off, and I dont have a timing light, so I timed it by eye, I think the timing is retarded, the car just doesnt have the snap that it used to). My other question is, how do you set the idle speed on a holley carb? Any help would be greatly appreciated, Thanx