Venezuelan President Carlos Andres Perez, touring key petroleum-exporting states in an effort to bridge a divisive spilt over crude oil prices, left Tehran today with no evidence of any substantive progress so far toward a compromise.

Perez told a news conference before departing for Iraq, the fifth stop on his six-country tour, that he is "optimistic" that differences over prices would be resolved at the next meeting of the Organization of Petroleum Exporting Countries in Stockholm Jyly 12-14. He repeatedly dodged questions on what results he has achieved, and specifically on whether Saudi Arabia has accepted any compromise.

"The concrete result is that there is no danger of any kind that the unity of OPEC will be broken," Perez said. "Likewise the problem of the two-tier price system will be resolved at the proper time."

OPEC unity, however, has never been a major issue in the price split, not even after last December's OPEC conference broke up in bitterness with Saudi Arabia and the United Arab Emirates insisting on only a 5 per cent oil price increase while the 11 other members adopted a two-stage 15 per cent rise.

Saudi Arabia's Crown Prince Fahd reaffirmed this commitment to OPEC unity during Perez's visit to that country before coming here. A day after Perez left Riyadh, however, the official Saudi Press agency distributed a newspaper editorial warning that Saudi Arabia would not change its price position.

Informed sources in the Perez party said the Saudis were sticking to their price policy because they still hoped to reap some political benefit from their moderate position when Prince Fahd visits Washington in about a month. The Saudis would also lose face within OPEC by backing down. The 11 with higher prices have so far managed to maintain them because of Saudi inability to immediately raise production.

Oil exporters are now entering a slack season, however.

Perez said that oil exporters are awaiting the results of the final between developing countries and the richer industrialized nations in May before deciding if a further oil price increase is justified. He said continued inflation in the industrilized world would "provoke a very grave situation" that would hurt all developing countries. President Carter's energy policy recognized "this world reality," he said.

Iranian oil officials also welcomed the Carter policy. They said it justified higher crude prices and could serve to undermine the Saudi position at the next OPEC conference.