Value for each model is a little different...
Will give you and over veiw of price's... Without updates like Late model engine like LT1 or LS1 etc.... And 5 lug wheels and front disc brakes...I'll try to give %'s after to add to each.
#1 condition, restored or just rolled out of the showroom floor..
19,500 Fleetside 18000.00 Stepside
#2 condition, restored or modified could win local shows better than a Daily Driver...
12600.00 to 14000.00
#3 Daily driver nice clean old paint not to many modifications
7000.00 to Few mod's and good paint 11000.00
#4 Starts Runs Drives and Stops Straight driven every once in a while and is needing TLC...Primered dented some rust...
3000.00 to 4800.00
#5 DOA... But complete, some rust, Deduct for missing trim or bumpers engine ETC......
1500.00 to 2200.00
#6 Parts truck.... Not much left very little rust but has title might roll migh not...
475.00 to 780.00
Prices cover 1/2 ton and 3/4 ton Factory V8
If it Has a 6 cylinder deduct 20%
If it has Factory A/C that WORKS add 10%
If it has aftermarket A/C add 2%
If it has newer style front disc brakes & 5 lug converstion add 5%
If it has Posi or Limited slip rear gear (rear end) ad 2%
64 GMC SWB.....327 2 x 4's ZZZZZZOOOOOMMMM
...........