HELP...Will not idle in gear

If the marks are right, then retarding it will just make it worse.

So to recap, from previous posts;

A) Verify that there are no vacuum leaks, where air is getting into the engine that is not controlled by the throttle plates.Such as the booster system,the PCV system,the base gasket and the intake manifold, or a falling-apart carb., or any other vacuum systems.
B) Verify that the low speed circuit is working.I usually remove the mixture screws and blow a little compressed air in there.A couple of short,low volume bursts will dislodge dirt stuck in the airbleeds.The low-speed fuel circuit is usually OK, but this too will be cleared with the air.Be gentle with the air.
C) Verify the timing marks, and the timing systems.
D) Saved for last is a valve lash adjustment and compression test.
E) And if all else fails, a Leakdown Test.

These are listed in the sequence I would do them.