383 running like s#%t.

Hey guys, sorry I haven't checked in for a couple days. I didn't get a chance to work on it yet, it has been raining since Saturday. The truck has been sitting for 2 years. I would start it occasionally to keep the oil flowing in the motor. When I finally got it on the road, a couple weeks ago, the gas tank was empty so I filled up with fresh gas. There is a filter between the fuel pump and carb. I changed the filter but it is still doing it. At idle it sounds like I can hear the dead cylinder(s) kick in and out through the exhaust. I have an IR heat gun to check each cylinder and a compression gauge. As soon as it stops raining so I can work on it I will post back. Thanks guys.