Conservative groups have begun trying to turn last week's contra aid vote into the Panama Canal of the 1980s -- a legislative loss they can parlay into a slew of election wins.

"This is exactly the kind of vote we like to see even if it goes against us," said Paul Weyrich, chairman of the Free Congress Political Action Committee (PAC) and a leading movement conservative.

"There are people who voted against this bill who are going to pay for their vote with their congressional seat this year," he continued. "If anyone thinks that's an idle threat, I suggest they look at how we defeated those liberal senators in 1978 and 1980 by using their votes on the Panama Canal. It's going to be the same thing all over again."

To make good on the threat, David Keene, chairman of the American Conservative Union, yesterday sent a letter to 50 conservative groups proposing a "summit meeting" to decide who among the 222 House members who voted against the Reagan administration's $100 million aid package should be targeted for defeat.

Meanwhile, conservative direct mail fund-raiser Richard A. Viguerie said yesterday that he plans to send 10 million pieces of mail on the contra aid issue during 1986 and added that he expects the issue to be his No. 1 dollar-producer for the year.

"We haven't had a galvinizing issue like this for some time," said Viguerie, who, like most conservative direct mail fund-raisers, had a lean year in 1985. "In a year or two, the Democrats are going to regret what they did."

A spokesman for Weyrich said the conservative groups will focus their electoral efforts on vulnerable liberal Democrats and on Republicans whom they feel betrayed their cause. High on the hit list, said a spokeman for Weyrich, are two of the 16 Republican who voted against the aid: Rep. James Ross Lightfoot (Iowa) and Rep. Sherwood L. Boehlert (N.Y.). Both received money from conservative groups in the past.

Keene said yesterday he is well aware that polls consistently have shown a majority of the public opposes the administration's aid package, but he argued that the numbers are misleading. He cited a survey taken two weeks ago by conservative pollster Arthur Finklestein which found that, once people are told that the Soviets and Cubans have poured hundreds of millions of dollars into supporting Nicaragua's Sandinista government, public opinion shifts to 2-to-1 in favor of aid to the contras.

"Once the people get the facts, it's very clear where they stand," he said. "And we know how to get them the facts."

Keene said that in addition to making campaign contributions and direct mail appeals, the conservative groups would produce television and radio ads for airing in targeted districts.

He and Viguerie also said they think that even if the House approves a compromise aid measure next month -- as many believe it will -- the issue will be alive in November. "We're not going to let anyone forget that vote last week," Viguerie said.

In fund-raising, however, the rule of thumb is that one profits from losses; some conservatives believe that a turnaround vote next next month would muddy the picture.

Moreover, some conservatives doubt that the issue has the potential that Weyrich and friends say it does for touching raw nerves.

"People just don't give a damn about Central America," said Bruce Eberle, a prominent direct mail fund-raising consultant to conservative groups. "The Panama Canal was compeletely different. People perceived it as being American property. This issue doesn't have near the emotional impact."

Democrats, for their part, say the White House effort to turn the vote into a for-or-against-communism showdown has "backfired," in the words of Democratic Congressional Campaign Committee Chairman Rep. Tony Coelho (Calif.). Democratic strategists say they don't think that conservative operatives can succeeed where President Reagan has failed.