302 engine trouble (timing?)

I have a 1980 F150 4WD that I have recently put a new 302 motor in. The company that I bought the motor from is a reputable local company that I have done business with before. However, the new motor runs pretty rough and timing seems to be off. The previous motor ran good with the exception of worn rings. The new motor is a long block with new cam, lifters, bearings, ect... I can not get this thing in time. I have set it to top dead center countless times and checked the timing (which is off). The truck will not idle on its own. I have replaced the plugs, wires, cap, rotor, distributor and checked the coil. All of the plugs are getting fire, but, it still runs rough. It does not start very easy and I have to keep the motor at about 1000 rpm to keep it running. It also will not run unless it is at about 30 degrees below top dead center. As I was saying before, the previous motor ran pretty good. It is getting plenty of gas and I can not find any vacuum leaks. It isn't smoking and it is not backfiring through the exhaust or carburator. I would appreciate any help that you can give me.

I'd probably move the distributor a tooth either way and see what it does