I’m guessing your model number is actually 70EL76D, am I correct? If so, you have a 1976 Johnson 70hp. I’m not quite sure what you mean by tiller handles, but am guessing you want to convert these engines to tiller control, am I correct? I don’t think OMC started offering tiller controlled 3 cylinder engines until the late 80s, but could be wrong. Nonetheless, I’m sure the parts from the later model would bolt onto your mid 70s engine. Unfortunately, these pieces will be tough to find used, you might have better luck in the NW corner of the US or perhaps on some Midwest lakes. These pieces are very expensive as well.
Look at this website to see the pieces I am thinking of:
http://www.marineengine.com/parts/johns … 60ttl+Only