12,500 FANS AREEXPECTED TO SEECLEVELAND CARDBob Pastor, No. 1 Heavyweight Contender Faces Cleveland’s Jimmy Bivins,CLEVELAND, April 15—No less than 12,500 fight fans will pay upwards of $50,000 to watch Bob Pastor of Saratoga, N the No. 1 heavyweight contender, and Cleveland’s Jimmy ■ Bivins, top-ranking light-heavyweight challenger, slug it out in the 10-round bout Friday night at the local Arena, all of which is unrefutable evidence that Cleveland now is the nation’s boxing hotspot.Less than 18 months ago a crowd of 2,000 for a local boxing match was an occasion for a civic holiday, but now, thanks to the matchmaking genius of Larry Atkins of the National Sports Enterprises, Inc., sellouts are becoming the rule rather than the exception.Friday’s mitt-biil, from top to bottom, is another well balanced program guaranteeing the fight fans their money’s worth from the 8:30 p. m. opening gong.In the 10-round semi-final spot is another main event if there ever was one. It matches Anton Christoforidis, ex - light-heavyweight champion, and Cleveland’s Jimmy Reeves, former international A. A. U. middleweight king. Museato vs SavageSergeant-Joe Muscato, Buffalo* heavyweight white hope knockout sensation, faces rugged Jack Savage of Oakland, Gal., in the featured preliminary of six rounds. Rematched for five heats are Johnny Lawer, unbeaten local middleweight, and Tommy Yarosz of Mon-aca, Pa., kid brother of the ex-middleweight champion, who had his win streak halted at 19 straight by Lawer in their last meeting.Opening the card in a four round heavyweight bout are Gus Mullner, 1941 Cleveland Plain Dealer Golden Gloves light-heavy-weight champion, and Jack Kelly of Hot Springs, Ark.