has a link to a California births data base. It has two Robert Organs born in Los Angeles in your time frame:
Last_Name First_Name Middle_Name B_yr B_mo B_dy Mothers_Last_Name Sex County_of_Birth ORGANROBERTBENJAMIN19521223HUNTMALELOS ANGELES ORGANROBERTTHOMAS19530508PENTLANDMALELOS ANGELES
If you have your own birth certificate, and if it has your father's middle name on it, and if it matches one of the above, you have another clue. If not, I've raised your hopes needlessly, and I apologize.
Realistically, if he was a heavy drug user in 1977, there is a good chance he is dead now. The chances of him being clean and sober enough to operate a computer these days (or a tool with sharp edges, for that matter) are slim.
There isn't an Organ born in 1951, 1952 or 1953 on the SSDI
that fits your father, so he may be still alive. (Click on "Advanced" to try the search yourself.) He may not be alive; drug abusers do not always die in surroundings that make it easy to identify them.
You have put your age and your desperation out here for the world to see. Please be careful. Be especially careful of men claiming to be your father and wanting you to either meet them at a freeway rest stop or to send them bus fare.
If you do make contact with anyone from your biologic family, for goodness sakes go very slow, don't reveal your phone number or street address, and insist on meeting, if you do, in large, public areas.