I myself have just recently gone thru this question-I also have 8 hp honda-#1000584----first off I believe 8hp started in 1987 or 1988-I was told the numbers on transom bracket only tell you what year production started-and they maintained this mode of numbering untill 1998-I was told mine was between those years---not much help---sso I called honda outdoor equipment" gave same numbers to them -they right away told me I had a 1988 long shaft-and gave me another number to request a owners manual [free of charge]-mailed to me in 1 wk I received---hope this helps-would love to keep in touch with our common motors----------------------jancsi-----
