Changed intake gasket, now it won't start

Some data and more info is needed at this point; I don't think anyone here has the history of the underlying problem(s).
- How about some history in this engine?
- What were the symptoms prior to changing the intake?
- Has the engine run well before?
- What idle RPM now?
- How did you check for the spark in post #1? If you connect a wire to a plug in open air, that is not a valid test. You need to see if a spark will jump a 1/4" to 3/8" gap in open air.
- Have you checked the vacuum level in the manifold after the gasket change? If not, get a vacuum gauge and check it at idle.
- Going backwards on the timing and having it run better is odd/unusual.

This is going to need an approach of gathering accurate baseline info.