I've got a 455 Olds sitting on a pallet. It's a complete engine with fresh crank and bearings, everything else looked new when I took it apart. It seems to turn over normally when the spark plugs are out and I turn it over by hand with a ratchet, it spins real fast by the starter with no spark plugs in it. Once the plugs are in it seems to turn over real slow with the starter. The pistons have the largest dish in them that I've seen on an Olds piston so it has to have pretty low compression ("Ka" heads). Do 455 starters use shims? It melted the negative battery post on the battery last night and I didn't crank it over for more than 30 seconds at a time. WTF?

Could be the actual cables, but the grounding point is definately not bad. Starter is new. I'm wondering if the gears on the flywheel and starter are too close causing binding... 

But why would it bind 30 seconds into it? Probably the starter gets hot, pulls more current, and the battery isn't up to the task.

I think you miss-read my post but it really doesn't matter because you're right and that's what counts.