81 Pontiac LeMans won't start

[Mike hammy23]

I had an oil leak around my distributor so I put new o-ring in it and a new seal changed all my spark plugs new valve cover gaskets new intake manifold gasket and now my engine rolls over but will not start

 

[melsg5]

did you test if the distributor is producing a spark?
you are sure you reconnected the plugs wires to the correct cylinders?