By Geoff Mayfield

LOS ANGELES (Billboard) - Kanye West looks set to win the closely watched duel with rival rapper 50 Cent for the No. 1 slot on next week's U.S. pop album chart, according to preliminary sales data issued Wednesday.

West's "Graduation" sold an estimated 437,000 copies during its first day of release Tuesday, ahead of 310,000 for 50 Cent's "Curtis" and 107,000 for country star Kenny Chesney's "Just Who I Am: Poets and Pirates," according to a new "Building Chart" devised by tracking firm Nielsen SoundScan.

The Building Chart gives an early look at how the race is shaping up for SoundScan's final charts, which post projected national sales each Wednesday morning, extrapolated from a panel of merchants representing more than 90% of the U.S. music market.

Some pundits project West will surpass 750,000 copies for the week, breaking the 2007 record of 623,000 copies held by rock band Linkin Park's "Minutes to Midnight." But West did better with his last album, 2005's "Late Registration," which debuted with 860,000 copies. 50 Cent also will fall far short of the 1.1 million start for his last album, 2005's "The Massacre."