Replacing the clutch?

[bluesfella]

I have a '66 C10 with the 250 straight six and three-on-the-tree manual. The clutch just went out, so I need to replace it this week. I have two basic questions:

1. How do I know if I have the 10" clutch or the 11"? It looks like both are available everywhere I check, but without pulling mine apart I have no way to tell which one I have.

2. Is there a simple walkthrough around for doing this? I've pulled engines and transmissions in a few cars, and even did a full rebuild on the 700R4 tranny in my BelAir, so I'm perfectly comfortable with automatics, but I've never replaced a clutch before. Any info specific to these trucks would be especially helpful.

Thanks in advance! I'm not able to get on this board nearly as much as I used to, but I know this is the place to ask!