By PHIL LUSIGNAN Of The News Staff Following ratification Tuesday night of a tentative agreement with Gulf Oil Corp. by the office workers group of the Oil Chemical and Atomic Workers Union, Local 423, area union representatives were meeting Wed nesday morning to proofread the final language of the proposed new two-year contract. The office workers were the last of the four major bargaining groups to ratify the ten tative agreement worked out by company and union negotiators late Friday in Washington, D. C. Their okay reportedly came with a standup vote during a 6 p. m. membership meeting Tuesday. A Gulf spokesman Wednesday morning said it could not be determined exactly when the union members would return to work until after the contract had been officially signed. No contract signing meetings had been scheduled Wednesday morning. Relis Stelly, chairman of the workmen’s committee of Local 423’s main plant group, said Tuesday that the tentative agreement brought no changes in the financial package or the pension plan that was offered in Gulf’s “final offer,’’ but that some changes were reflected on local issues. Under the proposed contract, union members would receive a 75 cent per hour raise upon returning to work, plus a four per cent pay hike July 8. The contract calls for an eight per cent pay raise and a wage reopener the second year if the Consumer Price Index exceeds five per cent of its Jan. 1, 1976 level. The pension plan, which was a major stumbling block in the negotiations, calls for combining the old voluntary contributory plan with the company paid pension plan. The union in their negotiations, objected to the combination contending that veteran members of the plan would not realize as great an increase as would newer members. Overall though Stelly said union members thought they had worked out a “pretty good contract,” and said he was satisfied. The work stoppage entered its 99th day Wednesday, the longest strike in the history of Port Arthur refinery.