Stephen D. Bechtel Jr., chairman of the Bechtel Group Inc., one of the nation's largest construction firms, was the guest at a recent lunch with editors and reporters at The Washington Post. The following are selected excerpts from the luncheon conversation:

Q. How is the president's tax plan going to affect you?

A. It's going to complicate our lives. I've been working to try and figure out for our employes what the net effect will be on the company, and I haven't seen an answer on it yet.

The big thing it's going to do is complicate the dickens out of our accounting and tax report . . . if we can't pool all your foreign incomes, it's going to be a real bearcat.

Q. Why is that?

A. Because the way it is now, if you have a loss in one country, you can offset all of that and pool it all. And you can offset foreign taxes against U.S. taxes.

They're saying you're not going to be able to do any of that -- as I understand it. We know it's going to be a severe impact. . . .

Q. To go from that to the larger issue of the economy, do you think the economy is being well managed by the Reagan administration?

A. Yeah, I think you can find faults. I think overall they're doing real well. I think, frankly, the biggest problems facing our country and, in fact, the world are the two deficits in the United States -- the budget deficit and the trade deficit. And I think that's casting a cloud over the future here and therefore around the world. I guess I'd be willing to go along with some still-large deficit as long as we get on this course of getting down to where it's very small over the next several years.

Q. The same with the trade deficit? A I don't know. That's a bigger problem.

Q. If we've got a serious problem with these two deficits that you are talking about, why do you reach the conclusion that things are being so well managed?.

A. I think I said "except." And I think there is an inability of the administration to get the things I think they need to continue that. And I don't want to get in a debate on the tax program, the budget and all that. Frankly, I'm not much on that, but frankly, you're all sitting there and tracking all this stuff. There's a helluva a big difference between what the administration wants and what the House wants.

Q. But the president, I think it can be fairly said, has never made a statement such as you made -- that those two deficits were one, related, and two, are serious problems that something needs to be done about.

A. Well, I don't know that I can agree or disagree. His spokesmen sure have. I think generally where they are so far . . . is not that good, but it's not bad. The employment is up overall, I guess, at an all-time high the last time I saw the numbers, there were people working. We are creating new jobs every year. I don't know what, one or two million new jobs a year or something like that. We're doubling our exports. And I think right today we are living with a deficit, but I think it shadows the future.

Q. Are you convinced that the administration shares the same concern that you do?

A. I think so. I'm not that close to them, frankly, but I sure hope they do. Some of them do, but I'm not sure.

Q. Are you surprised when you read that your two former employes, Defense Secretary Caspar Weinberger and Secretary of State George Shultz, are thought of as archenemies engaged in bureaucratic warfare?

A. Say that again?

Q. We often write about them being on the opposite sides of the question.

A. Oh, between the two of them? It's different types of people. They have different responsibilities to the government, and both are very strong intellectually. They are very independent thinkers. They are also good soldiers. I think some of this has been pumped up a little bit, more than what it ought to be. Not that I have been that close to either one of them since they came back here.

Q. There have been people that we've talked to who describe Shultz as having a real personal animus toward Weinberger.

A. I'm not really that close to either one of them now, and you're here so I won't, I can't debate that. But I know they had great respect for each other when they worked for us.

Q. When you are working around the world and dealing with another governments, what assumptions do they make about current relationships between Bechtel and the U.S. government?

A. This guy owns it.

Q. What do they assume and what would you like them to assume? A Well, like we tell 'em, if we have any suspicion they're expecting us to do anything for them with the U.S. government, we tell them no way. Our people are under orders they can't go to Shultz or Weinberger on anything, anything affecting Bechtel business, client business or U.S. government affairs.

And, frankly, I've got to say, I think we pack a burden because they are there. A lot of people think it is a great thing for us, and frankly, we are very proud of it. I think it is a great compliment to our organization that the president and his people go to one company for two cabinet level officers in the same administration. That is, I think, a great compliment to our organization.

We don't do that much government work, I think it's less than 2 1/2 percent. I think when we're up for consideration on government work there has to be a pretty clear case for us, because I think the bureaucrats tend to take the safe way out and not take a chance on being accused of favoring Bechtel. And that is a personal opinion, I can't document that.

Q. Do you see any hope in the way manufacturing companies have started to change the way they are doing business?

A. Yeah. I think the fact that GM is moving out the way they are, going to the Saturn program, and they bought Hughes Aircraft and paid a bunch of money for it. And the fact that they went in with Toyota in California on that joint plant. The Japanese are running it. They reworked their labor deal. They said it was an old plant, outdated. But it was one of the newer plants they had there.

Q. There are some, particularly in the media, who claim that if General Motors had spent an equivalent sum of money as they spent for Hughes and Ross Perot's company on improving the process by which they made cars, then the domestic automobile industry would be thriving. Do you have a view on this?

A. I don't know the numbers, but I would quarrel with that conclusion. I think that when you look at a company like General Motors and the history and the esprit de corps they have there, to get General Motors into something different, or doing things differently than what they had been doing is a monumental job.

And I think to bring that about only from within is maybe impossible. I have to tell you, I'm not quoting anybody, this is my own conclusion, knowing GM Chairman Roger Smith a little bit I think he's taking the bull by the horns and is really trying to do something with GM which is a very courageous effort.