F250 Coil Problems!!

Hey! I got a 1980 Ranger F250 that my dad and I have been rebuilding for awhile now......couple years actually and it's still not done :banghead: However we've been making progress lately and the recent problem we're having right now is with the coil. For some reason it keeps burning up and we don't know why :confused: Any comments or suggestions could really be useful to us.

get a coil with the resistor built into it. toivo