The House, in what some lawmakers see as a significant change of mood, yesterday passed a money bill that provided $1.3 billion less than the Pentagon requested.

The ranking Republican on the defense appropriations subcommittee, Rep. Jack Edwards of Alabama, said that a spinoff from the House's effort to cut overall government spending in today's Proposition 13 environment is a growing reluctance of members to add money to bills once they reach the floor, even when weapons specifically requested by the Pentagon are at stake.

As competition intensifies for dollars within the spending ceilings Congress establishes for itself, Edwards predicted, "the defense budget may lose its immunity to cutting." In recent years the Pentagon has been getting almost all the money it has requested from Congress as administration leaders warn of a Soviet military buildup.

"Something funny is going on here," said Rep. Robert N. Giaimo (D-Conn.), chairman of the House Budget Committee and member of its defense appropriations subcommittee. "We're in some kind of mood change."

Giaimo predicted that individual members will have a tougher time from now on in trying to add money to the totals approved by House subcommittees, as the drive for balancing the federal budget takes hold.

The Pentagon requested $2.4 billion in extra money, not counting pay increases, and the House approved $1.1 billion. The House figure is below its own previously approved budget ceiling for fiscal 1979, and is expected to be at least $500 million under what the Senate will approve.

The $1.3 billion was taken from weapons programs that are usually generously funded by the House. The cut included $192 million for Navy missiles; $97 million for the Navy to replace money it took from other accounts to pay the contested bills of shipbuilders; $87 million in operating funds, and $42 million to buy spare parts for the Pratt and Whitney F100 engine in the Air Force F15 fighter.

"Under the old makeup of the defense appropriations subcommittee," Edwards said, the amendments he and his allies sponsored to restore those cuts would have passed easily. Last week, however, they lost by a 5-to-4 vote.

The subcommittee's new chairman, Rep. Joseph P. Addabbo (D-N.Y.), complained that the Pentagon has not spent the money Congress appropriated in past years and therefore its request for more should get a critical eye. Addabbo replaced George H. Mahon (D-Tex.), who retired.

Other old friends the Pentagon has lost to retirement include Robert L. F. Sikes (D-Fla.) and John J. Flynt Jr. (D-Ga.).

Also, Rep. Daniel J. Flood (D-Pa.), who has been in the Pentagon's corner for years, is so occupied with his court troubles that be seldom attends meeting of the subcommittee, on which he is the second ranking Democrat. He also has been in and out of the hospital with a variety of ailments.

The two new Democratic members of the House defense appropriations subcommittee, Rep. John P. Murtha (Ap.) and Norman D. Dicks (Wash.), are less predictable on Pentagon votes than the old lions they replace, according to members.

On the Republican side, the subcommittee's most outspoken hawk, Rep. Jack Kemp of New York, is so busy campaigning for what may turn out to be a presidential bid that fellow members put him in the "no show" category on most subcommittee votes this year.

Edwards sees a new coalition forming among conservatives who believe the voters really do want government spending reduced and liberals who are targeting the Pentagon budget to offset what they consider unfair cuts in social programs.