Steering pull

I have a 1970 duster that pulls hard to the right when driving. When i put it on stands and start it the steering wheel turns to the right at a fast rate. Not too long ago there was a thread about this and someone said to loosen a bolt and bump something with a hammer until the wheel centers out. I don't know what bolt or what to bump with the hammer. Can someone set me straight on what to do? Thanks in advance--dusterdowns--steve