With only half the schedule gone, the 1977-'78 Ivy basketball race is over--Penn, 8-0, and at least three up on every team in the loss column, will win this year's title. But that doesn't mean Harvard will roll over and play dead, because what may be the two most exciting games of the year will take place tonight and tomorrow night when Princeton and Penn hit the IAB hardwood.

The hard-luck Tigers (10-9, 4-3 Ivy) invade tonight, when the Crimson hopes to avenge an 83-64 defeat at Jadwin early in reading period.

Princeton is stinging after losing to Columbia, 38-36 at the buzzer two weekends ago, and has dropped out of the Ivy League race for all intents and purposes. It has been a tough year for Pete Carril's Tigers, who have suffered all but one of their losses by fewer than five points.

Feisty coach Carril said after the Columbia loss, "I can't recall another season like this one in 23 years of coaching." All-Ivy senior Frank Sowinski leads Princeton into the contest with a 17- point average, helped out by a supporting cast of center Bob Roma (14), forward Bob Kleinert (nine) and guard Bill Omelt-chenko (nine). The Tigers' defense ranks second in the nation, holding its opponents to fewer than 55 points per game.

Penn may be even tougher Saturday night. The Quakers have won eight straight and 13 of their last 14, the lone loss coming in the form of a two-point heartbreaker against powerhouse Providence.

All-American candidate (Kevin Mc-Donald (22 points per game, seven rebounds), Tony Price (16 and 9.5), and a pair of forwards lead an All-Star cast for the Philadelphians.

Although the Ivy title's out of reach, a win in either contest would make the season, if not great, then certainly good for Harvard.