It depends on the truck.
Here's the NADA value for a LWB C10, I left off the options, so you can add what you have that's listed and it'll adjust the price. http://www.nadaguides.com/Classic-Cars/1981/Chevrolet/C10/Pickup-1-2-Ton-LWB/Values
Here's the SWB C10 pricing if you have this style. Again, add whatever options you have. http://www.nadaguides.com/Classic-Cars/1981/Chevrolet/C10/Pickup-1-2-Ton-Shortbed/Values
Then, and I've never used this option before, you can look up "All P/U's values from '81" and it's different than either the LWB and SWB. You'll have to add the options again. http://www.nadaguides.com/Classic-Cars/1981/Chevrolet/C10/PU-1-2-TON-ALL-MODELS/Values
This should cover anything you need to know about the value of your truck since KBB won't go back this far. The only other thing you could do is have your insurance agency come out and appraise it, or have a shop do it.
I'm selling my '81 for about $5,500 as-is (crack in windshield is mainly the only thing that's wrong with it), or after I replace the glass and fix the exhaust I'm listing it for $6,950 OBO. Naturally, wash and wax it before you sell it. People have A.D.O.S. (Attention Deficit-Oooh! Shiny!).
no ECM's in a 1981
No it will not. total different designed engines.
any seat belts from an 1981 through1987 Chevy truck or 1981 through 1989 blazer or suburban
no, the body style changed in 1988 1981 thru 1987 are the same though
Between the bottom of the windshield and the top of the dash on the drivers side.
Who said it won't ? It will fit right in there with NO problems
try www.haynes.com
in the fuel tank
SAE 10w30 any major brand.
Mounted in the center of the distributor cap.
It holds 4 quarts>
mine weighs 3634