The tilt and trim was introduced during the 1975 model year. You can find the description on various 1975 and more recent models. The systems were sold as a kit for use on earlier motors but were/are not listed in the OB Accessories until 1975. http://shop.evinrude.com/
You might find one at a salvage yard. americanoutboard.com
budgetboats.net
fairwindsmarina.com
laingsoutboards.com
marinepartsoutlet.com
mmmarinesalvage.com
piratemarinesalvage.com
outboardexchange.com
outboard-parts.com
salvagemarine.com
sea-way.com
Superior Marine (800-338-9281)
tcoutboard.com
trixieslanding.com