Case W-20C Years of Manufacture ???

For whatever reason, regardless of maker, finding accurate definitive information on construction equipment is almost impossible; no matter how I word my question, all I get are page after page of the same equipment trader ads.
If I do finally stumble upon some useful details, there is never any mention as to which years something was made.

At the particular moment, I need to know which years the Case W-20C was made.
Sounds simple enough doesn't it; I have worn my eyes and keyboard out looking.

During this search, I have also ran across some serious discrepancies as to the engine.
The few specification sheets that I have found all state that a 504ci Case A504BD is used; however, I have found numerous for sale and auction listings that claim a 6B Cummins; none of these ads state whether the Cummins is turbo or not.

Does anyone know of a site that has good details on Case equipment, or equipment of any and all brands for that matter ? 

Thanks for reading and all help is appreciated.

JoeM(GA) wrote: I found this at "toughquip.com"

THANKS !
I am bookmarking that site.
I went there, selected Case, typed in W20C, and engine/size and years of manufacture immediately popped up.
I haven't tried any other makes/models, but I feel like that site is going to be a big help.
Thank you.

wjohn wrote: It may not tell you years but Case has specs and brochures available on their website for a number of older models.

Thanks !
I checked all three versions of the W-20C and none of them ever came with a 6B Cummins.
Although Case used the 6B (and still does) in many models of their equipment AND farm tractors, there is no mention of it ever being used in the W-20C.
Yet, I did see several sale ads claiming Cummins power.
Since Case does use the Cummins in so many applications, I don't guess it would be any monumental task to swap one into a W-20C.

Was not called a Cummins but a Case Engine, have to remember that Cummins bought Case small engine line for their own early in the 80s but Case independently continued production of their own engines for some time. These tractors would be Transitional as well a difficult issue for finding parts from either producer as each would insist was the others product.