Charlie,Some aftermarket 12v kits have a 'fusible link', basically a sacrificial wire that burns out first to save the rest of the system.
Did you smell any burning after the initial sparking?
The link is usually found connected to the starter.
Might be worth having a look.....


1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.