I have a 1984 F150 with a 300 6 in it..the other day i had some smoke coming from under the hood,i found that some wires where laying on the manifold...i had it towed in and the stealer said it was a burned coil,i had it towed home replaced the coil and still won't fire, it cranks but won't start.
What could it be?

I take it you do not have any spark? Well if you are not having any spark coming out of the coil, check your wiring, inductive pickup, and get the ignitino module tested, i know napa will test them for free.