The selenoid is grounded to the fender apron with its attaching bolts. The negative battery cable has two terminals on it besides the battery clamp. One is on the end and it attaches to a bolt on the engine block just behind and below the alternator. The other is about 12 or so inches from the battery clamp and is grounded using one of the bolts that holds the voltage regulator to the fender apron. The starter does not have a seperate ground for itself.
The Duraspark system grounds directly to the engine through the distributor, so while not having a good body ground will mess up a lot of other things, it won't be the problem with a no spark issue!
I never have seen a ground strap going to the starter from the factory. If the starter is grounded separately then the distributor is grounded because the block is made from conductive material. A 10awg ground strap is too small. It needs to be the size of a battery cable or it will melt
A 10 AWG strap is fine to test. Every comet I've owned had a ground wire going from the starter to the block in the same boss the battery cable grounded too. If that wasn't factory I'm sorry, I've only owned 2 and I should probably have kept my mouth shut.
Ok everyone, I'm happy to say.....success! It was in fact the (drum roll please) ignition switch in the base of the steering column. Went to Autozone and got one for $23. Thanks to everyone, I learned a lot.
