Harvard's undefeated varsity lightweights and once defeated varsity heavyweights get a final chance to find out which are really the best crews in the East when they travel to Lake Quinsigamond for the Eastern Sprints tomorrow.

The heavies will be seeking their sixth straight Eastern Association of Rowing Colleges (EARC) title, and the lights will be defending the championship they won at last year's Sprints.

Predictably, Harvard's heavies have been seeded number two behind the powerful Penn boat which beat them by a length and a half in the Adams Cup race last week. It was the Crimson's first lost to a college crew since 1963.

Harvard is also seeded second behind undefeated Navy in the J.V. heavies race, and second to Penn in the freshman heavies competition.

Lights Top Seeds

The Crimson lightweights grabbed the top seeds in all three classes. Penn was rated second in both the varsity and freshman races, and M.I.T. was picked as the runner-up in the J.V. division.

As usual, Harvard's major challenge for top honors will come from Penn. Both the Quaker varsity heavies and lights have yet to lose this spring. But Harvard will into have to worry about either Penn crew until it makes the finals.

The varsity lights is the most balanced class of the entire Sprints, with at least four other boats capable of giving the Crimson quite a lot of trouble.

Harvard races in the first heat against Rutgers. M.I.T., Cornell, and Dartmouth.

Big Red Hibernates

M.I.T. gave the Crimson a running battle before losing by only 4.2 seconds to Harvard in an early-season encounter. Cornell, a late-starter every year because of the lingering Ithaca winters, lost by only a few feet to M.I.T. in April, and dropped a race to Penn before rebounding to beat a competent Princeton boat.

Perennially a big, well-coached boat, the Big Red always seems to reach its peak in time for the Sprints, and have finished first in the lightweight division three out of the past five years.

In the other varsity heat, Penn and Yale are the strongest boats. Since the top three finishers in each that qualify for the finals, the race for the championship will probably pit the Crimson against these four boats and one also-ran, maybe Princeton.

Penn will be especially dangerous in the lightweight finals since it will be aiming for a sweep to complement a possible sweep in the heavyweight division.

"We're apparently a few seconds faster then the other boats." Coach Stephen Gladstone said. "It would be no surprise to me if the boats in the finals all finished within a length of each other," he added.

In the heavyweight class, Harvard and Penn should have little strain in qualifying for the finals. The Crimson will race in the second heat against Brown. Wisconsin, Columbia, and B.U. The winner and runner-up in each of the three heavyweight heats makes the finals.

Princeton and Cornell will probably make the finals, but the only competition that really matters will be between Harvard and Penn.

Crimson Coach Harry Parker has been moving rowers around within the shell in an effort to discover a more consistent rowing combination than the one which lost last week.

With the promise of good rowing conditions tomorrow, the Crimson will row in their Stampfli shell for the first time this season. The low-profile Stampfli rides faster in the water under calm rowing conditions.

Harvard plans no strategy changes and will row at its usual high stroke for the race.

Penn has made no line-up changes in the past week, and the same boat that trounced Harvard in Philadelphia will face the Crimson at the Sprints.

But Penn Coach Joe Burk is far from over-confident. "We'll row about the same way we did last time," he said, "but Harvard is bound to be better. We had every advantage last week."

"In good weather, they are an extremely good crew," he said