Some of the South's most powerful pololiticians signaled their former comrade, Jimmy Carter, yesterday that he will have a hard time stopping the Tennessee-Tombigbee Waterway.

Four governors - George C. Wallace of Albama, Ray Blanton of Tennessee, Julian Carroll of Kentucky and Cliff Finch of Mississippi - testified before House and Senate Appropriations subcommittees in favor of the $1.6 billion project that would link the Tenneessee over with the Gulf of Mexico.

And Southern senators and representatives who are accustomed to getting much of the pork in the congressional pork barrell gave them a warm Exception. Sens. John C. Stennis (D-Miss), James B. Allen (D. Ala), John J. Sparkman (D. Ala.) and James O Eastland (D. Miss) and Rep. Tom Bevill (D. Ala.) all showed determined support for the project.

The "Tenn-Tom," as it has become known since it was first authorized by Congress under President Truman, could link the Tennessee and Tombigbee rivers in northeast Mississippi and Western Albama, creating a 253-mile waterway to the port of Mobile.

So far, $276 million has been appropriated and $23 million spent on the system of canals, locks and dams. Another 157 million is proposed for the fiscal 1976 budget that goes into effect Oct. 1.

Tenn-Tom is one of 30 water projects that Carter said he would like to halt because of what he said were safety and environmental problems and low economic benefits.

However, the governors and senators who packed the hearings yesterday - only one person spoke against the project in the Senate hearing - said the waterway would bring economic prosperity to one of the South's poorest regions.

The project is supported by the people of Alabama. It would be good of the whole nation." said Wallace, equating it with the Tennessee Valley Authority, which provides electricity to seven Southern states.

Mississippi has spent $25 million to relocate roads and bridges for the waterway. Firch said, "Now the federal government is telling us that we will change horses in the middle of the stream. All I can say to Mr. Federal Government is that the people of Mississippi are living up to their part of the agreement, and we expect you to do the same."

Carroll said Tenn-Tom "will open up one of the major areas of coal production in Alabama, Tennessee and Kentucky" for easy transporation to market.

The governors cited a study for the Appalachian Regional Commission claiming the waterway will create some $135,000 new jobs by the year 2000.

However, Randall Grace of the Tombigbee River Conservation Council in Starkville, Miss., testified tfor project opponents that it will have "few, if any economic benefits."

Grace said costs escalated from an estimated $316 million in 1969 to $1.64 billion in 1976. The Corps of Engineers, which is building the project, says it will produce $1.15 worth of benefits for every dollar spent. However, Grace said this figure is artificially high because costs are calculated on a 3.25 per cent interest rate.

The project will require moving 280 million cubic yards of dirt - more than was removed for the Panama Canal, Grace said. He added that 104.587 acres that the corps must acquire for the waterway will be removed from local tax rolls.

Furthermore, he said, the project "constitutes a unique subsidy specifically for barge traffic. The barges pay no user fees to cover any of the costs associated with building or maintaining the canal."