I WAS GOING through some old files today when I came across a page from a reporter’s notebook.

It didn’t look like much and I was about to throw it out when I realized what it was: Part of my notes from a 1980 news conference by George Bush when he returned to Houston after being selected by Reagan as his running mate.

At that session, Bush was asked whether he though Reagan’s economic plan was “voodoo economics,” as Bush had claimed during the campaign. Bush’s reply: “I never said that!”  He not only claimed he had never said those words, he challenged anyone to find a tape of him saying that.

I went back to the newsroom and wrote a story about that, and The Post had put it on the front page. Then I started to have doubts about it, because other news outlets had ignored Bush’s strange denial.

I began to get real worried when Bush tried to pass it off as a joke, one that I obviously hadn’t gotten. But if it had been a joke, it had fooled a key Bush aide I had talked to in reporting the story. She was obviously troubled by his denial and said so.

Fortunately, the story got picked up by the wires and the TV networks were able to get hold of footage of the news conference that showed clearly Bush was not joking.

My story had included interviews with several national political reporters, all of whom said they had heard Bush used “voodoo economics” at various times during the campaign, but I was never able to find a tape.

However, Ken Bode of NBC-News dug up a clip of Bush uttering the words and introduced it with the words, “Challenge accepted” on the network’s evening broadcast the next day.