hole in dizzy cap, then split plug wires

[bert0427]

My truck is a 1986 ranger 4x4 with a 2.9l and I have just replace my head gaskets on my 2.9l that came off of craigslist for 300$... this thing has me stumped. it spits sputter and miss fires randomlyand puts out black smoke when it dose this and sometimes white . i have repaced plugs, wire cap, rotor button, replaced the fuel injectors (injectors are used). but here is the big problem .... my distributor cap had a hole blown threw it so i replaced it... then i just had a brand new sparkplug wire split right in the middle ??? also the 1st cap that got a hole was on the #5 spark plug post on the cap .. then once i replaced it the wire that got split in half was the #5 plug wire
any help or ideas would be great. thanks very much for your time , also i am accepting any 302s for donation to this truck lol ..