What do I have?

[68greg]

Hello, I'm kinda new to the forum joined in Dec of last year but haven't had a lot of time to browse the site till now. I'm currently deployed to iraq and I keep having this nagging question about the 68 stepside I bought right before leaving. I think the truck has a later model frame it has disc brakes,rear leaf springs,and the motor sits farther forward than I think it should. I'm sure this question has been answered before, but how do i know what frame i have and where do I look for a number. This knowledge would be helpful when it comes time to buy parts to rebuild this thing.Thanks in advance for any help