Crosman corp has schematics and some parts available on-line through their home page. Click on the link below and when it opens, at the bottom of the page, click on "Download a manual." There you will find the information you are looking for.
Crosman has some parts available online. See the link below for all the Crosman rifle parts manuals and owners manuals. You can order parts from Crosman.
There are 4 different versions of the 66 Powermaster by Crosman. See the link below for all the Crosman rifle models, parts list and owners manuals https://support.crosman.com/hc/en-us/search?utf8=%E2%9C%93&category=200223634&query=powermaster
I checked the Crosman web site (WWW.Crosman.com) and It says that some parts are still available. You part cost $4.58. Go to crosman and click on "download a manual" find the drawing for the 66 and then contact crosman customer service and see if you can order it.
There are several versions of this model. Here is the web page for all of Crosman air guns. Owners Manuals and Schematics. See the link below.
The CROSMAN 760 Powermaster started production in 1966 then went through 8 different changes and ended in 1991
You need to state what condition it's in. without more information it is not possible to answer you.
You can find a parts diagram on the CROSMAN homepage. Click on "Download a manual" (at the bottom of the page ) There you will find an owners manual and parts diagram for the model 66. Parts are still available through Crosman. See the related link.
Crosman makes about 50 different '''RIFLES''' you need to state the model you are asking about. See the link below for Crosman rifle owners manuals
It all depends on the current condition of the rifle. You have not given description so it is not possible to give an estimate of value
You have two choices. First: Crosman has the parts manuals online along with the owners manuals. (See the links below) there are several versions of the 760 so look at each one to find yours. Then contact Crosman for the parts you need if they are available. (Customer contact.) Second: If you have no luck with that, Crosman offers a free service to locate shops that repair old Crosman products. So see the 3 links below.
The Remington Airmaster is rated at 725 FPS (Feet Per Second). The Crosman 760 Powermaster is rated at 595 FPS and the 760P is rated at 600 FPS. 10 pumps each.
Crosman 66 Powermaster: 100%=$80, 95%=$65, 90%=$45, 80%=$35, 60%=$20 (50%= no value) Blue book of Airguns