440 78 truck???

Where to look to see if its factory 440? I have had my truck 16 years but never looked in all the datails of it. What I mean is, unlike the cars, I don't see a VIN tag under the hood to get any options off of.
Once I finish or get where I wanna be on the dart, I will start on my truck. But if the 78 is worth more fixed up, factory 440, I would fix it and sell for money to get my truck project underway. I just need more info. Where on line can I find more info? Thank all for the help so far.