front main seal

[Tony Genovese <chaztg@earthlink.net>]

Hey guys & gals,
I just found out from Mossy Nissan here in San Diego that they no 
longer stock the front crankshaft seal for an R16 motor.
Are there other ways to get this seal; can the H20 one, or a similar 
item from a contemporary Toyota motor work? There just have to be 
other ways to get this simple yet critical part for this common motor.
How may other parts like this have been discontinued?

Tony
 '66 1600