When President Carter fired W. Michael Blumenthal as part of his much publicized cabinet shakeup last July, the reason officials gave for the unexpected switch was a desire by Carter intimates to have a Treasury secretary who would be "loyal" and a better organizer as well.

Although Blumenthal had battled hard for Carter's policies, he ran afoul of the Georgia mafia for allegedly not being enough of a team player. Carter also complained in private later that his Treasury secretary was inept as a manager. "He couldn't run a meeting," the president is reported to have said.

Now, after revamping his economic policymaking team to put former Federal Reserve Board chairman G. William Miller in the top Treasury slot -- with Paul A. Volcker, onetime undersecretary of the Treasury for monetary affairs, to succeed him at the Fed -- Carter may have gotton more than he bargained for.

Although insiders say Miller is more the "good soldier" loyalist than Blumenthal and is exhibiting more of a take-charge style, it still is unclear whether the new secretary has as much depth as his predecessor on fundamental economic policy issues.

Moreover, with Volcker at the head of the Fed, Carter is having to accept far more independence on the part of the central bank than he would have if Miller had remained at the helm -- leaving the administration with considerably less flexibility than it would have had before.

Carter was all but forced to appoint Volcker as Fed chief to help quiet the uncertainty after he fired Blumenthal question of style and procedure -- particularly for Miller. But now they're going to have to get down to substance."

last July. But while the choice was a masterstroke politically, it has some drawbacks for the White House. Volcker is a sterner inflation-fighter than Miller and has the clout to make it stick.

As a result, while the dynamic new duo may be working more effectively than the old Blumenthal-Miller team, it also could wind up pushing Carter into significantly different policies than he might have followed otherwise -- possibly costing him the election if they go awry.

"The real testing hasn't begun yet," says one longtime observer who has kept tabs on Carter's economic policy problems. "So far, it's been mainly a

At first blush, naming Miller to the Treasury post and Volcker to replace him at the Fed has marked a decided improvement in both cases. Miller, a former businessman with little privious exposure to monetary policy, seemed out of place at the Fed, where he often stumbled and drew criticism in the markets.

More the politican than Blumenthal, Miller has adapted easily to the Treasury secretary's more front-line role, moving promptly to strengthen ties with key congressmen and labor leaders, and building rapport with other cabinet officers -- skills not often cited as a strong point of his predecessor.

He's also had a major impact in bringing new order to the administration's cabinet-level Economic Policy Group, which had been in varying stages of disarray during Blumenthal's tenure. (The EPG is the administration's highest economic policymaking body.)

While Blumenthal allowed EPGers to stray to any subject they wished, insiders say Miller has run the policy-making body crisply, plowing determinedly through its agenda. "It's the first time we've had a manager in this administration," one admirer says. "We're getting decisions -- and on time."

Miller also has moved to soothe ruffled feathers at Labor and Commerce by inviting secretaries F. Ray Marshall and Juanita Kreps to re-join the EPG after having been dumped from the board by Blumenthal. (Importantly, however, neither one is on the EPG steering committee, the key policy setting arm.)

And the new Treasury chief has acted quickly to allay uncertainty within his own department. Caught in the middle by White House blundering after Blumenthal's firing, Miller immediately announced all top aides would stay on indefinitely, with no plans for subcabinet dismissals.

Perhaps most important to Carter's Georgians -- and most disconcerting to those outside the White House -- the new Treasury secretary also has been the ultimate good soldier and Carter loyalist, committed, as one insider put it, "to the Camp David admonition that we all have to pull together."

As a result, in line with Carter's stated desires, the Treasury chief has barred any discussion of a possible tax cut within the EPG, despite the closing in of policymaking deadlines. And he's carefully avoided any confrontation with Carter's Georgia mafia.

It's in the area of substance, however, that Miller remains untested. The only major policy issue the new secretary has grappled with so far has been the Chrysler Corp. bailout, where he quickly took command and deftly pushed the administration into a quick decision.

He also had admonished colleagues against "more of those grand ideas that won't get anywhere," such as the administration's ill-fated proposal for "real wage insurance," which died in Congress earlier this year only a few weeks after it was unveiled.

But skeptics argue the Chrysler issue was a natural for Miller -- "It's a business question, and Miller's a former businessman," says one key strategist who watched the new Tresury secretary at work -- and the wage-insurance decision was an easy one for anyone not intellectually committed to the plan.

How well Miller is able to cope with broader economic policy issues -- such as whether to recommend an anti-recession tax cut -- remains to be seen.Miller went through much the same difficulties at the Fed, where he first was hailed for his openness, then critized for not seeming to understand the issues.

Last week, the new Treasury chief startled outsiders by downplaying the likely impact of the recession, saying he thought the recession was half over and saw no "strains" yet on the U.S. economy. "If that forms the basis of his policy decisions," one insider frets, "we could be in trouble."

Volcker, by contrast, has begun his term at the Fed far more aggressively -- with a hard-line, anti-inflation stance that has spawned a series of new interest rate hikes aimed at dampening loan demand and reining in the runaway money supply.

Much more low-key than was Miller in the job but clearly more steeped in economics and monetary matters, Volcker has brought the markets and inflation hard-liners just what they asked for -- the rejection of Miller's go-slow money and credit policies and the resumption of previous Fed thoughness.

The worry that some critics are raising is whether Volcker has gone too far in his interest-boosting moves -- a question probably neither he nor anyone else will be able to answer for months, until the impact of the Fed's recent actions begins to take hold.

But therein lies a potential rift between the two new Carter appointees. So far, Miller has remained silent on the Fed's actions, passing up all opportunities to criticize the Volcker policies despite their risk to the administration's game plan.

But insiders concede that all that could change soon if the economy begins to worsen beyond Miller's expectations.

During his own brief tenure as Fed chief, Miller admonished the White House to rely on an easing of monetary policy if recession came rather than shifting to a tax cut or more spending. But Volcker, hemmed in by inflation and the threat of a new decline in the dollar, can't make that assurance.

As a result, Miller may find himself having to oppose the tight-money policies Volcker is pursuing -- unless the new Fed chief shifts his course, which, for now at least, doesn't seem very likely. By election time, Carter may find himself sorry he changed his team at all.