(MONEY Magazine) – Q. I am over 55, and I plan to marry a widower whose house is up for sale. When my fiance, who is in his sixties, sells the house, he will take his one- time $125,000 capital-gains tax exclusion on the profits from the sale. We want to live in my house after our marriage, until I can retire in four years. If I sell my house in a few years, will I also be entitled to the one-time exemption for house sellers over 55? IRMA LEE SILVERMAN Metuchen, N.J. A. No. You can take the exemption only if you sell your house before you marry. If you don't sell your house, yet marry someone who has used this tax technique, you will gain a husband but lose a tax break. To the Internal Revenue Service, the exclusion is a one-per-couple deal.

Q. How can I invest in the tunnel under the English Channel? JOHN J. CAPOZZI Boonton, N.J. A. Hold off until July, when $1.14 billion of shares in Eurotunnel, the English-French consortium that plans to build a double railway tunnel link between Britain and France, are expected to be available on the London and Paris stock exchanges. You will be able to buy them through most U.S. brokerages, which can purchase shares on foreign exchanges either directly, if they have a seat on the exchange, or by using an agent who does. For the time being, Eurotunnel shares will not be sold on U.S. exchanges as American Depositary Receipts (ADRs), which are usually the most convenient way for Yanks to trade selected foreign stocks. If you decide to invest, expect to pay 2% on top of normal transaction fees, making small trades uneconomical. Keep in mind too that currency fluctuations can raise or lower the dollar price you pay -- or get -- for stocks that trade in pounds or francs. What is more, the project has received a lukewarm reception in the City of London, the British equivalent to Wall Street, and is politically controversial in England as well. If the British allotment of shares does not sell out, construction of the so-called Chunnel could be held up or even canceled.

Q. I bought three Indiana Housing Finance Authority bonds yielding 10% in 1985 for $15,000. They had a call date of Jan. 1, 1996 at a premium of $2.50 for each $100 of face value. To my dismay one bond was called on Nov. 1, 1986. I got back my $5,000, plus $166.67 in accrued interest, but no premium at all. How could this happen? J.H. COKEWOOD South Bend, Ind. A. Your bond, the 1985 Series A issue for single-family residences, was called early without premium, a possibility provided for in its offering prospectus. The call came early partly because some of the issue's funds were not expended & and some of the mortgages the bonds backed were prepaid, causing monies to flow back to the Indiana HFA. Exactly which bonds got called (by serial number) was determined by lottery. Premiums are rarely paid on early calls. According to Steven Beligratis, research director at John Nuveen & Co. investment bankers in Chicago: ''Housing bonds are notorious for early calls, especially when their rates are more than two percentage points above the going rates on available mortgages.''

Q. In 1975 I insulated the walls of my house with urea formaldehyde foam, a type of insulation that was later banned by the U.S. Consumer Product Safety Commission as a known respiratory irritant and suspected cancer-causing agent. The ban was lifted in 1983, and I believe that enough time has passed so that the foam in my house is harmless. Still, is my house worth less because it was insulated with the foam? If so, can I get my tax assessment changed?

CHARLES DAVANT III Blowing Rock, N.C. A. Your house may be worth less than it would be if it had not been insulated with UFFI or if you had removed the stuff. A study by Runzheimer International, a relocation consulting firm, found an average reduction of 13% in appraised value of houses with UFFI. An appeal to your county tax assessor's appeal board may result in a reduced assessment and a lower tax bill.

Q. I have seen no mention of head-of-household filing status under the new tax law. Will it still exist? If so, will tax rates for individuals using that status still be lower than the rates for single people? STEPHANIE WALL San Jose, Calif. A. Yes, to both questions. A head-of-household filer with $38,000 of taxable income, for example, will pay 18% less tax in 1987 than if he or she filed under single status.

Q. Do any mutual funds exist that specialize in commodity futures or stock index futures? EDWARD MUSANTE Minneapolis A. Federal regulations restrict mutual fund trading in commodity and stock index futures. Thus no publicly traded mutual funds can truly be said to specialize in such investments. Even so, some funds -- such as Dreyfus' Strategic Income and Strategic Investing funds (800-648-9048) -- use index futures to enhance income. Others, including Oppenheimer's Quest for Value (800-862-7778), use futures solely for portfolio hedging.

Q. If a dividend payment is to be made on April 1, say, and the dividend will be paid to stockholders of record as of March 1, who gets the dividend if a shareholder as of March 1 sells his stock between that date and the April 1 payment date? RUSSELL V. FAIR Springdale, Ark. A. It depends. If the dividend payment per share is for an amount less than 25% of the share price, the shareholder of record on March 1 receives the dividend, even if the stock was sold afterward. If the distribution exceeds 25% of the share price, however, or if there is a stock split, the cash dividend or the certificates for the shares acquired in the stock split would belong to the new owner of the stock. These rules keep sellers of shares in companies that might pay a big dividend or make a split from getting a higher price for their shares and keeping the windfall too.

Q. I own a brick that I think came from the Yellow Brick Road in the movie The Wizard of Oz. I understand it was acquired from the studio in l979. How can I authenticate my brick and, if it is real, find out what it is worth? VINCE MASTRACCO Santa Cruz, Calif. A. According to Aljean Harmetz, author of the book The Making of the Wizard of Oz, the paved surface of the road to the Emerald City was probably painted, so one side of your brick should have yellow paint on it. Harmetz points out, however, that it is unlikely that components of the sets, such as bricks, would still have been at the MGM studio or on the film lot in 1979, some 40 years after the film was completed. Thus to authenticate the item, you need a receipt or some other form of documentation to show when and how the brick was acquired from the set. Sotheby's auction house estimates that if your brick is the real thing, it might fetch $500 to $700 at auction.