Parts for ancient 8hp

[<David Hay>]

I have an old 8hp, model 8A
Serial number 647S 06143, probably from 1970's. It needs a new water pump (conmplete) and head, but the catalog only goes back to 1984.
Are these parts still available?
If not, can later water pumps parts be substituted?

[<David Hay>]

Sorry - new head gasket, not whole new head.

[floater]

David,
You may want to try Twin City Outboard
http://www.twincityoutboard.com
These guys specialize in finding older parts for outboards. They have treated me fairly and have helped me out in the past.

[<A.S.>]

part number 655-W0078-B0 water pump kit