In a compelling sign that the Republican tide on Tuesday will produce a historic sweep in the House, the final pre-election poll by the Gallup Organization gave the GOP a 55 percent to 40 percent lead over Democrats among likely voters in its generic congressional ballot test.

The commanding 15-point advantage makes a Republican takeover “highly probable,” and could produce GOP gains “anywhere from 60 seats on up, with gains well beyond that possible,” according to the Gallup analysis released late Sunday.

Gallup’s Oct. 28-31 survey of 1,539 likely voters, which was conducted with USA Today, documented an increase in the “enthusiasm gap” between the two parties. The survey found that 75 percent of Republicans and independents who lean Republican are “absolutely certain” they will vote in the 2010 midterms, compared with 68 percent of Democrats.

In recent years, the turnout gap between the two parties has been 2 or 3 points. In 1994, when Republicans gained 54 House seats from the 1992 results, Gallup’s final pre-election poll showed a 67 percent to 62 percent “enthusiasm” lead for Republicans.