Abe Pollin has gone guaranteed-win night 39 dates better and declared the Capitals' next NHL campaign sort of a guarranteed-safisfaction season.

"I am prepared to put my money where my mouth is to prove to you that I mean business" in assuring that "by next year the Washington Capitals will become an exciting, compeitive, improved hockey team," club president-arena owner Pollin has written season-ticket holders - and announced that anyone who buys a season ticket and feels he has not recelved full value may obtain a 20 percent refund at season's end.

Pollin aims to sell 10,000 season tickets compared to this year's total of approximately 4,700. But there is a trade-off for the refund plan, in which 20 percent of season-ticket revenue will go into an interest-bearing account in the Citizens Bank & Trust Co. of Maryland (all interest revenue to be donated to Children's Hospital; just call the bank for refund): no more 10 percent discount, as has been accorded those who buy their 40-game ration in advance . . .

J. Brent Clark, the former NCAA Investigator turned House subcommittee staffer and anti-NCAA witness in the same subcommittee's probe of the association's enforcement pr.ocesses, has resigned and gone home to Oklahoma.

A special staff task force assigned by Rep. John E. Moss (D-Calif.), subcommittee chairman, concluded after six weeks of investigation and interviews with 30 witnesses that Clark's testimony was "deficient and should be corrected and clarified" in the hearing record. Rep. Norman Lent (R-N.Y.), an outspoken critic of Clark, released the confidential report yesterday - pointedly noting it was turned in April 24, and that Clark quit April 24.

Clark testified as leadoff witness at hearings of the House Commerce Committee's subcomitttee on oversight and investigations that NCAA investigators "routinely cajoled or even bribed" athletes to help amass "evidence" against colleges not in favor with NCAA officers. The task force found "bribe" an inappropriate and misleading word and other Clark allegations improper and unsubstantiated.

Clark wrote Moss that he was resigning because of his engagement to a young woman with two small children, whose patience had run out . . .

Virginia Tech, an independent since it dropped out of the Southern Conference 13 years ago and frustrated in bids to join the ACC, has been accepted into the Metro Seven Conference - it is a sevensome again with VPI replacing ACC-bound Georgia Tech to join holdovers Lousiville, Cincinnati, Florida State, Memphis State, Tulane and St. Louis. Metro Seven is basketball oriented, doesn't even have a football championship, the Tech will be a contender for the 1978-79 conference laurels although it has only St. Louis on its schedule. Hopes are to schedule two more Met-7 teams and have seven outside games designated to count in the standings - to determine seeding in the conference postseason tournament . . .

Karen Simmons, one of the Don Dell firm's own and experienced in managing pro tournaments, has been named tournament director for the Washington-area part of the Decade National Amateur Team Tennis Championship. The event begins June 30 at 33 sites throughout the country, each team including three men and three women, minimum age 21 except for two players per team who must be at least 35, Matches will consist fo one set (eight games wins) each of men's doubles, women's doubles and mixed doubles, giving amateurs a shot at advancing to regionals at Pinehurst, N.C. thence to national finals Sept. 10 at the new U.S. Open site in New York, Flushing Meadows. Entries close June 17 . . .

And after the NFL draft, the "13th round": The Redskins signed yesterday as their first free-agent pickup after the draft wide receiver Dwight Allen of Bethune Cookman. Mark Murphy anc testify that being a "No. 13" - first nondrafted collegian signed - can be significant . . . Conspicuous by absence from the list of 334 conscriptees: All-Americas Zac Henderson, Oklahoma safety and Randy Simmrin, USC wide receiver. But, if they're healthy and not Canadabound, they are probably in the same boat as Maryland's rugged but untapped defensive tackle from Oxon Hill, Ernie Salley. The draft hadn't been over a half-hour, Salley said, before he had been contacted by 10.

It was a long wait for the Bullets to make Sports Illustrated's cover, but this week's issue not only features Elvin Hayes but Phil Chenier's jersey - inside out, worn by Mike Gale of San Antonio the night the Spurs lost some of their shirts before losing the finale in Cap Centre . . .

Died: Joe Bedenk, 80, Penn State's baseball coach 1931-62 (won 410 of 577 games) and head coach 1949 (between Bob Higgins and Rip Engle among 25 years on the Nittany football staff . . . Mary Ellen Baer, 74, widow of 1934 heavyweight boxing champ Max Bear, in Sacramento. Only last month, a Sports Illustrated recollection of Baer related how he met Mary Ellen when she "managed the coffee shop in Washington, D.C.'s Willard Hotel."