so i went and changed my spark plugs and wires ( was running before) then after i put the new stuff on all it will do is crank and back fire no start i gapped the plug double and triple checked the firing order is correct. any ideas where could be wrong?

 

Make sure your number 1 wire is in the right place. If you are off one or two, even if your order is correct, it will do what you describe.

Also, make sure you went the right way with the firing order. Check the rotation of the rotor, and make sure you are going that way. (I have a good story about that if you have insomnia and are into pathos....)

 

U didnt mess with the distributor?? Is it tight? Doesnt move back and forth? Just new plugs? If u just changed plugs and nothing else. 1 of probably 3 things.... did u replace a plug then put the wire back on? One wire one plug at a time? U could hsve broken 2 or 3 plugs. Or the freak option..... timmi.g chain jumped........ just make sure your firing order is right.
My thought

 

He has two posts about a 390 problem. One here in computer chips & tuners section and the other in the 385 series section. Maybe he can't find them again....???