Lou Whitaker and Kirk Gibson each homered and drove in three runs as the Detroit Tigers beat the Boston Red Sox, 9-3, last night in their Tiger Stadium competition for second place in the American League East.

Winner Walt Terrell (8-2) issued eight hits in 7 1/3 innings, walking two and striking out two. Aurelio Lopez came on for his fifth save.

Loser Dennis (Oil Can) Boyd, bidding for his fifth straight complete-game victory, gave up 11 hits before leaving, also after 7 1/3 innings. His record dropped to 8-5.

The Tigers built a 4-0 lead through three innings and Terrell worked out of a bases-loaded jam in the second as Detroit won its eighth of 10 games and gave the Red Sox their second successive defeat but only the fourth in their last 21 games. Detroit remained in second place, 2 1/2 games behind Toronto, and moved a game ahead of Boston.

Alan Trammell singled in the first, advanced on Gibson's sacrifice and scored on a single by Lance Parrish. Tom Brookens hit a two-out double in the second and scored on Whitaker's 10th home run, into the right field upper deck. Leading off the third, Gibson drove the first pitch off the facing of the third deck in right for his 13th homer.

Gibson doubled to set up a run in the fifth, Whitaker had an RBI single behind Brookens' triple in the sixth, and Gibson's two-run double keyed a three-run eighth, Trammell scoring the last run on a passed ball.