Engine hasn't ran in years has idle problems?

I just got my 95 ford f150 302 engine running for the first time in about three years. I had to fix the timing because it was 180 off. I found TDC and had the rotor pointed at #1 cylinder. Now the engine starts but does not idle. When I turn the key it fires right up but only lasts for a couple seconds unless I idle it high. The engine does not have the Y pipe exhaust on it right now with no o2 sensor plugged in. After idling it a little high to keep it going there's a little smoke (this worries me)

You probably need fresh gas. Gasoline doesn't have that long of a shelf life. Also try plugging in an O2 sensor. It helps monitor the air/fuel ratio. Maybe it won't run without receiving input from that O2 sensor.

An engine that old and sitting for that long. It can be anything. Clog lines to sensor going bad. Your just going to have to trouble shoot it until you find the problem. No one is going to be able to give you an answer here or anywhere.