[KMK454]

First off, what is the asking price?

I just bought a 78 C10 Silverado, 17900 original miles, all original. Did a ton of market research on it first...

I found that book value says around 7k for my truck, but it has no mileage factor at all. The same book also says classic GTOs, etc., are worth less than 10k.

So a standard "book" test isn't worthwhile. There are classic car books (gold book or something like that, I forget its name but I used it). This will tell you some more.

I found a "show-ready" example of my truck would go for anywhere from 9 - 12k. This means a restored, concourse ready vehicle. Also, original low-mileage, unrestored, or rare option groups would add value to this.

As you can see, things are getting very gray...

My truck was advertised at 16k. I worked the price down to 12k by waiting it out over several months and finally making offer after offer. I'm not sure if this is a "good" price or not, but I met a guy at a gas station who seriously offered me 13k for the truck just 1 week after I bought it, so I don't feel bad about what I paid for a time-capsule driver of a truck. Also, I bet if the dealer I bought from wanted to wait, they could eventually sell it for that 16k. It's just a matter of finding the right buyer.

I also checked some auctions online and found similar trucks going for anything from 8 to 20k.

Your truck in question is a 1983 K30 with a 454. The heavy-duty K30 aspect, to include 4x4, will surely add value and appeal. The 454 option is a rare and desirable one. Most people tend to prefer the short wheelbase models, though, with "work trucks" bringing in fewer dollars. Also, 1983 is, in many states, a year that still requires emissions testing, etc.

If you could post more information about the options, condition, and maybe some pictures, we could help a little more.

If I were you I wouldn't pay more than 15k for it... but I don't know enough about this truck to say that for sure! Here's my advice:

Research that specific year of Chevy truck. Research auctions for similar trucks online. Research Classic Car Value books. Research KBB value. Inspect and analyze the truck thoroughly so you know what you're getting into. Finally, ask yourself what your goals are regarding this purchase, and then see if the truck meets those goals. Then set a maximum price you will pay for the truck and set your "preferred" price for the truck. Wait it out as long as possible and prevent emotional attachment to the vehicle... be willing to walk away and hope for good luck!

Don't get frustrated in your research: information on old truck values is hard to find, but with some patience and google, it can be done.

Who is the seller? A classic car vendor? Or some farmer emptying the barn? They may or may not know what they have here.

Edit:

Also keep in mind, while 11k original miles is great, it can easily mean nothing. Check the following:

Paint: is it original or a repaint? If original, how bad is it? If a repaint, is it documented, the same color, and a quality job?
Body: is it rusting? Accidents? A car this old will be hard to find records of accidents. Look for clues such as general panel alignment (factory alignment was pretty crap back then though), unusual welding, "new" screws or bolts, etc.
Suspension/Motor: are these parts all original? If so, have they been maintained, or will you need to do a full overhaul to get this thing running? If not original, are these items rebuilt, replaced, or modified? Are the replacements stock pieces or different?
Interior: is the interior original and in good condition? Does the AC/Heat/Radio/Gauges work? If things aren't original, were the replacements factory correct?
Options: is the color combo desirable or rare? Is the drivetrain desirable or rare? Are the interior options desirable or rare?

All of this seems like mundane, common sense-type stuff, but there is a LOT to consider when buying a classic low-mileage vehicle like this. Each of these factors could swing the price up or down by a thousand bucks or so!