VATICAN CITY -- The conclave that elects a new pope is said to be swathed in unchangeable tradition. But the cardinals who meet on April 18 will enjoy a far different experience than did those who elected John Paul II in 1978.

The cardinals that year were housed in a cramped, dank building near the Sistine Chapel. The conclave --120 men, many of them elderly -- had to share six bathrooms.

This time, each of the 117 cardinals will have his own.

One of the members of the 1978 conclave, of course, was Karol Wojtyla, the man who became John Paul II. Being cooped up under those conditions was apparently not an experience he enjoyed.

So in recent years he ordered the construction of the Casa di Santa Marta -- a building on par with luxury hotels -- precisely for the purpose of housing a new conclave. It was, in a way, his parting gift to the cardinals.

The residence, which cost $20 million to build, has 107 suites and 23 individual rooms -- each with its own bathroom. Which room is given to which cardinal is determined by lot.

The casa, with its marble floors and antique furniture, is a far cry from the Spartan lodgings cardinals endured in 1978. Then, a reporter who visited the cardinals' living quarters reported that the rooms were dark and humid, and the windows had been sealed with pewter.

Each room had a single bed, 27 inches wide, and was furnished with a table on which stood a pitcher and a wash basin. Under the bed was a chamber pot for cardinals.

The Casa di Santa Marta is a buff-colored limestone building a short walk from St. Peter's Basilica and the Sistine Chapel, where the voting will take place. A bronze statue of John Paul II stands at the entry, one of the few features to distinguish this place from a commercial hotel.

The residence has a dining hall. Doctors will be on hand, as will priests, who will be available to hear the cardinals' confessions.

Because the rules of the conclave allow cardinals no contact with the outside world, they will find no telephones, radios or televisions in their rooms. But, for the first time, they will be allowed to roam freely through the Vatican rather than being confined to the Sistine Chapel or their living quarters.

But some Vatican observers see a possible downside. The comfort of the Casa di Santa Marta is such that the cardinals might not choose a new pope as quickly as they would otherwise.