The performance by former Los Angeles Police Chief Edward Davis the night of Jan. 30 in the conservative suburban community of San Gabriel suggests the arrival of a major new political force, carrying serious implications for California and perhaps even the nation as a whole.

Conservative Republicans who paid $25 for Mexican food at Panchito's restaurant to back Davis's campaign for governor were obviously delighted by their choice. The 61-year-old, physically imposing Davis has the star quality to excite Republicans possessed by nobody here since Ronald Reagan in his first run for governor in 1966.

More significant was what Davis did not say at Panchito's. There was little of what made him the nation's best-known police chief: the colorful language, the hard line against protesters, the denunciation of homosexuals.

This combination of charisma and restraint has made neophyte office-seeker Davis, who changed his party registration from Democratic only two years ago, the favorite in the five-man GOP primary for governor June 7.

The notion Davis might have any chance against Gov. Edmund G. Brown Jr. this year is privately entertained even by Democratic strategists. However, the more realistic concern among Brown's friends is the damage thaat might be inflicted d by the free-swinging police chief. While unlikely to win, Davis might well cut up Brown badly enough to seriously hurt his chances of challenging Jimmy Carter for President in 1980.

The reason is the theme of the Davis campaign: "Put the heat to Brown." Davis gave his San Gabriel dinner a small taste of what's ahead by charging an eccentric Brown adminstration with ruining the state's economy: "California has had all of its valves turned down by funny little people Jerry Brown has appointed," he declared.

Before the dinner, Davis gave us a larger taste, claiming there is "a Brown plan" to "turn the whole state into a Jerry Brown commune." The governor has packed the state regulatory agencies with "terrorists" who "know how to use power."

That is stronger medicine than is possible from Davis's more liberal, more conventional Republican opponents (including State Attorney General Evelle Younger and Mayor Pete Wilson of San Diego). Democrats fear Brown's attractively unusual personality can be pushed over the fine edge into eccentricity by the chief's expert use of ridicule. When Davis caricatured the governor's ascetic lifestyle as "Jerry lying on a beds of nails," he forecast his future course.

The Republican worry has been that Davis's invective will carry him - and the whole Republican ticket if he is nominated - into oblivion. He first attracted national attention in 1973 by proposing portable gallows to hang skyjackers right at the airports. Just last August Davis told appreciative prison officials: "I always felt the federal government really was out to force me to hire 4-foot-11 transvestite morons,"

Davis's advisers want no more of such colorful language, and the chief is cooperating. Whereas six months ago he would volunteer the importantof anti-gay rights, Davis now stresses the more prosaic "jobs" issue - and how Brown's policy reduces employment.

Three days before the San Gabriel dinner, Davis evoked a good response from a blaccckk group by stressing jobs. At San Gabriel, he supported an antibusing intiative but added, "I'm not going to run with it as a platform." He holds his tongue in public about his Republican foes (although it slipped out recently that he considers Younger, still the front-runner but dropping quickly, "as exciting as a mashed potato sandwich").

In no other major state would Davis have a chance. He lacks funds (although master fund-raiser Richard Viguerie has been retained), campaign structure and past party service. But the California Republican Party since 1966 has passed up its own to select such celebrated conservative ex-Democrats as Ronald Reagan and S.I. Hayakawa.

Davis's basic strength is revealed by his own appraisal that "while Texas tries to be the most conservative state, California is the most conservative state - for Republicans, anyway." Given that reality and his own apparent self-control, the chief has long since ceased to be a laughing matter for fellow Republicans and may prove deadly serious business for Jerry Brown as well.