1978 Chevy short box pickup, 4WD, SBC 350.

This is my first attempt at forums, so please be gentle...

I replaced the starter in my Chevy a couple of summers ago, and it only has about 50 starts on the new one. I took a trip overseas, so it sat for over a year, but then it started fun when I got back home last summer. I put a new battery in it (straight from the store), tried starting it, and nothing happens. The lights don't come on, nothing works in the cab, etc.

I checked the voltage at the starter, it was what I expected with a new starter.

I left the ignition switch on, crawled underneath it, and tried to jump it, and when I touched the big battery post with one of the little posts, the lights and radio came on, but it still wouldn't start (I had someone else turn the key while I was connecting them).

When I touched the battery post to the other smaller terminal, it just sparked a lot, like I was connecting the positive and negative posts on a battery with a screwdriver.

I'm leaning towards the starter or solenoid going bad somehow, but it was working fine just a couple of months ago, so I'm wondering if somehow a bad ignition switch would somehow cause these symptoms.....

Any help and insight would be greatly appreciated!