General Motors Corp. will complete its purchase of Hughes Aircraft Co. before the end of the calendar year, GM officials said yesterday.

There was some speculation this week that GM might delay the proposed $5 billion acquisition, the largest of its kind outside of the oil industry, because of questions raised by the Securities and Exchange Commission over how the auto maker intends to account for the purchase.

"We're not delaying our purchase of Hughes. We expect to have it completed before the end of the year," GM spokesman Clifford D. Merriott said.

Merriott confirmed that the SEC is examining the terms of the acquisition proposal but denied that the examination in any way would undermine the value of the 50 million shares of special class H stock that GM plans to issue to help pay for Hughes.

"There's not a whole lot to this. We're working it out with the SEC," Merriott said, declining to elaborate.

At issue is how GM plans to account for the $4 billion in "good will" money that it is offering above the estimated $1 billion value of the California-based aerospace and defense company. GM wants to charge the amount against earnings from its automobile operations over 40 years. The SEC reportedly is pushing GM to charge the big premium against the earnings of the subsidiary it has created to hold Hughes.

GM's auto earnings -- for example, $3.7 billion in 1983 and $4.5 billion in 1984 -- would make a better cushion. Earnings from its Hughes subsidiary, projected at about $500 million annually, would be overwhelmed by the $4 billion premium write-off. Going the subsidiary route thus could depress the value of the class H stock.

SEC officials yesterday refused to comment.

But David Healy, auto industry analyst with New York-based Drexel Burnham Lambert, said he agrees with Merriott's assessment that the SEC examination will not delay or seriously alter the deal.

"It's more of a bookkeeping quarrel," Healy said. He said there is a possibility GM "might have to rearrange some of the terms" of the Hughes acquisition. "But, I certainly don't think that it will keep the deal from going through," Healy said.