Classic/Antique Car Repair: Removing a harmonic balancer, phillips screwdriver, bolt heads

Question
QUESTION: I need to get the timing cover off of a chevy 235, but the harmonic balancer is in the way.  Usually with a harmonic balancer there is a bolt in the center that you just remove the bolt and pull the balancer off with a gearpuller.  with this 235 engine, the center of the balancer is a recessed hole where it looks like you would attatch a giant phillips screwdriver.  There is no bolt to remove. It is like the hole in the center of the balancer could be used like the old crank automobiles to crank the engine over.  so my question is how do you remove the harmonic balancer?

ANSWER: Is there two or three threaded holes around the center hole? Let me know.
Brad

---------- FOLLOW-UP ----------

QUESTION: To answer your question about the threaded holes, there are no threaded holes around the center hole.  The only thing that resembles that are what appear to be three smooth bolt heads that resemble big nail heads.

Answer
If it is what I am thinking of from your description, it is the crank adaptor that is threaded into the front of the crankshaft. We used to use a medium sized chisel and pick a spot on one of the ramps so that when tapping with a hammer it will turn in the opposite direction as when it was cranked. Once that is removed use a big gear puller to remove the balancer.
Brad