Ignition...I think, any auto leccys here?

I got a problem,

I got a 351C in a 79 Oz Falcon, it has electronic ignition and a factory Bosche coil.
It also has relay that puts battery voltage directly to the coil rather than go round the loom. However after 2 years, the relay crapped out. I fitted another one (70A this time) and off I went....for about 3 miles and it died again.

Being a tape and cable tie kinda guy, I just put a wire from the battery to the coil and drove home.

Anyone have any thoughts on what could be the issue?

I may just fit a switch in the dash so I can use it, but its bugging me.

Other than that the car runs great, (needs another 100hp as usual)

Yeap, cheers for that, i'll try a 3rd relay. Be just my luck to replace a dud one with a very nearly dud one. LOL!

probably safer to stick with an old style mechanical relay, the cheap $10 napa electronic ones are no good, the more expensive $30+ electronics work a lil better, but electronic parts have a tendency to fail without giving any signs before they do

I think these are the mechanical type, a plastic cube style bout 1.5 inches each side and 4 big terminals on the base.

I've used them for all sorts of stuff and had no probs.

I'll go with the theory that I replaced a dud with a nearly dud.
I've been off work last 2 days and havn't felt like playing cars. But I will make the effort to change it again.

If it blows the third relay It could be the coil arcing to the terminal and backfeeding high voltage through the relay or maybe just a shorted coil that draws more than 70 amps.
AL