The JC Higgins Model 45 was made by Marlin and is basically the same gun as the Model 336. Manuals are availabe from Marlin Firearms. The JC Higgins Model 66 was made by High Standard and is out of production. I have a manual scanned, and can email it to you. sales@countrygunsmith.net
http://www.histandard.info/manuals/sears/bashotguns/index.html
Under $150.
what is a J C Higgins Model 583.9 20 gauge worth
http://www.histandard.info/manuals/sears/pashotguns/index.html
go to http://www.histandard.info/manuals/sears/pashotguns/0434di50r.pdf
Up to $125.
50-160 USD
$75
looking for parts
The manual can be downloaded here: http://www.histandard.info/manuals/sears/index.html
It will not be easy to find a manual for a JCS Higgins 20 gauge bolt action model 583.15 shotgun. The company, JC Higgins is no longer around and has been replaced by the company, Ted Williams. The company, Ted Williams may be able to help someone find a similar model manual.
Retail tops out at $120.