BIG DEAL: General Motors and CBS have signed an agreement in which GM will be the sole automotive advertiser for college regular season and tournament basketball games through 1998. The deal, which will go into effect next fall, has been estimated to be worth $400 million.

NONSTOP HOOPS: As things stand now, Saturday may be the most saturated day of college basketball on television this season. Between noon and 1 a.m. early Sunday morning, 20 games are to be seen in the Washington area, ranging from Indiana State-Bradley to North Carolina-Duke.

Figuring a game lasts about two hours, the only basketball-free period is between 6 and 7 p.m. Although ESPN, Home Team Sports and CBS are to carry games all afternoon, the overexposure king is Northern Virginia Television, channels 53 and 56, which will total seven telecasts.

CHIP'S TIPS: Redskins kicker Chip Lohmiller, of all people, made the radio news reports Thursday night. When a military analyst was asked about the accuracy of a cruise missile, he said if the weapons were fired from Boston Harbor and aimed at the goalposts in RFK Stadium, they would be more precise than Lohmiller's kicks.

NOTES: ESPN will carry two American University basketball games -- Feb. 16 vs. James Madison and Feb. 23 at George Washington -- as backups to the network's ACC games, which will be blacked out in this area and shown on Channel 7. Last year's James Madison-American game at Bender Arena also was an ESPN regional game. . . .

HTS has expanded its weekday programming by more than four hours per day, now starting its day at 11:30 a.m. . . . ESPN won seven of the nine sports ACE awards, the equivalent to the Emmys for the cable networks.