Need help--truck won't start!

[morglan]

It's an 82 with a Goodwrench 350. It drove fine all day yesterday, but when I went to start it today, it wouldn't fire. It's getting gas, but when it turns over, it sounds funny--almost like it's turning over real fast.

I've recently (as in a couple months ago) replaced the distributor cap, coil, and ignition module.

I have not yet checked for spark (didn't have time this morning), but I'm pretty sure there is none.

What could it be? What would it sound like if the timing chain came off? Could that happen from just sitting overnight?

Help!