As the 1978 congressional election campaign gets underway, Republican hopes for substantial gains in the race for the House of Representatives have yet to materialize.

Since World War II, the party that holds the White House has lost some 30 to 35 seats in off-year elections. Although the GOP, nationally, is slightly stronger today than at election time in 1974 - the last off-year election - Gallup Poll findings at this time point to only modest Republican gains.

If the vote for the House were cast today. survey evidence indicates that Democratic candidates would win 57 percent of the vote nationwide and Republicans would win 43 percent, assuming a turnout comparable to those of 1970 to 1974.

While it would require a political revolution of the kind not witnessed sice early New Deal days to enable the Republicans to win control of the House, they can take some cheer from these deverlopments:

In every section of the country infaltion is cited as the No. 1 problem facing the nation. The dramatic rise in living costs during the 24 years the Democratics have had control of Congress offers the Republicans a Powerful campaign argument.

The energy crisis is named the second most important problem except in the states of the East and far West, where unemployment receives about the same number of mentions.

The continuing failure of Congress and the administration to deal with the energy Problem, with its inflationary consequences, provides still another arguments to use against Democratic candidates.

Finally, a presidents who has the popular approval of fewer than 55 percent of the nation's adults finds that his party suffers greater than normal losses in House seats. The last approval rating of President Carter as reported by the Gallup Poll was 51 percent.

Republican chances to win seats, as reported earlier, are greatest in the MIdwest, chiefly because more Democratic seats are held there by narrow margins.

In the South and in the West, Democratic are holing their strength. Actully, in the South the poll findings show the party slightly stronger than it was in 1974. While the South has cast its vote for some Republican candidates for the presidency in elections since World War II, voters there continue to elect a preponderance of Democratic candidates. Of the 121 seats in this area, Democratic congressional canidates won 89 to the Republicans' 32 in 1976. In 1974 the Democrats won 92 of the 121 seats.

Losses for the Democrats in Voting strength in the East parallel those found in the Midwest - 5 percent in both cases.