Rep. William V. Chappell Jr. (D-Fla.), new acting chairman of the House Appropriations subcommittee on defense, needed a place to live in Washington while he was buying a new house in Springfield. So he spent several months at the home of a longtime friend, Zack Shelley, a military lobbyist for General Electric Co.

Chappell said yesterday that he sees no conflict between his friendship with Shelley and his new role as successor to Rep. Joseph P. Addabbo (D-N.Y.), who died last week. He said he has no plans to avoid voting on matters involving GE defense contracts.

"I'm going to vote on the basis of merit, as I have done in the past," Chappell said. "I don't intend to give any preference to any person at any time . . . Someone is trying to take some cheap shots at me."

From January to March, Chappell said, he spent "about 25 or 30 nights" at Shelley's home when he was not in his Florida district. He said he has known Shelley for a decade and Shelley's Florida family since the 1950s, and that he insisted on paying Shelley a few hundred dollars in rent.

Unlike executive branch officials, members of Congress are under no obligation to disqualify themselves from voting on matters in which they have a personal or financial interest.

GE spokesman Bill Shumann said the friendship would not affect the way the company deals with the defense subcommittee. He said Shelley first got to know Chappell when Shelley was an Air Force congressional lobbyist.

Chappell, who frequently accepts speaking fees from defense contractors -- including $2,000 from GE in 1983 -- is widely viewed as more supportive of the Pentagon than Addabbo was, but he says he will emulate Addabbo in seeking "the biggest bang for the buck we can get." Movers and Rockers . . .

On his weekly schedule, it was penned as "lunch with Baker and Burd," and it sounded like Education Secretary William J. Bennett was planning an eyebrow-raising political meeting with presidential aspirant Howard H. Baker Jr. and Senate Minority Leader Robert C. Byrd. But when Bennett showed up at the Maison Blanche yesterday, the topic was not politics but music, and his luncheon partners were WCLY radio comics Jeff Baker and David Burd.

Bennett, a self-described "Cabinet expert on rock 'n' roll," was cashing in on his winning bet that he could answer an on-the-air pop quiz on pop. One source close to President Reagan's youngest Cabinet member said Bennett enjoyed yesterday's luncheon conversation on rock almost as much as he reveled in introducing Baker and Burd to the curious dignitaries who passed their table. Like Father, Like Son . . .

Robert O. (Bob) Bowen, son of Health and Human Services Secretary Otis R. Bowen, is the favorite to get the Republican nomination for Indiana secretary of state. A former county judge, he's following in the footsteps of his father, who was a GOP member of the Indiana state legislature and then governor for two terms before becoming HHS secretary.