CAST IRON Pulley 5878

[daveoman1966 3,762]

I am trying to identify this CAST IRON Pulley and need help.  It is pulley # 5878 and is for the old Double-D Shaft configuration.  I have two of these and they are NEW OLD STOCK...found in a box of other new pulleys.  This 5878 pulley is shaped exactly like the dome-shape 5877  (110846) pulley but it is bigger diameter.  The dia of the 5878 pulley is 3.75" and the smaller pulley 5877 is only 3.25" in diameter.   
Every on-line source I look at says "Discontinued", but they never show what it was originally used on....what mower deck, that is.
Can any body HELP....HELP   HELP

My direct email is:
daveoman@windstream.net

[chorusguy 227]

Part appears in 1965 42" side discharge parts list

[daveoman1966 3,762]

would that be deck # RM-425.  If so, Toro doesn't show a schematic.  The next in line...  RM-426 is shown, but the side pulleys on it are # 5877. 
Can you post a schematic of RM-425 .... 

[gwest_ca-(File Mod) 11,147]

http://www.wheelhorseforum.com/files/file/599-mower-rotary-42in-sd-1965-rm-425-om-ipl-snpdf/

The file is upside down at the moment. Got it fixed.

Garry Edited August 18, 2015 by gwest_ca

[daveoman1966 3,762]

EXCELLENT....   I don't git no better 'n this.   THANX LOADS.  
Actually, you've outdone all expectations...  I had antoher pulley...  a DOUBLE BELT Pulley with DOUBLE-D configuration that I couldn't ID either.  It is # 5876 and is a 2-belt pulley for the center spindle.  It is 3 1/2" dia on BOTH top and bottom pulleys.  As it turns out, it TOO is for the RM-425 deck.  I found it in the .pdf download schematic, along with the 5878 pulley.  Here is a pic of it...  Thanx for pre-empting my search to ID it too.
RM-325 is curious...  LT pulley is 5878 (3.75 dia)  Center is 5876 (3.5 dia)   and RT side is 5877 (3.25 dia).  Why...?  This has me REALLY BAFFLED....