What most links don't show is what party they were in. I did some research and found:
MEMBERS OF THE UNITED STATES SENATE
Walter F. George – Democrat – Guy who actually read the Manifesto into the record.
Richard B. Russell, Democrat
John Stennis, Democrat
Sam J. Elvin, Jr., Then-Democrat
Strom Thurmond, Democrat
Harry F. Byrd, Democrat
Willis Robertson, Democrat
John L. McClellan, Democrat
Allen J. Ellender, Democrat
Russell B. Long, Democrat
Lister Hill, Democrat
James O. Eastland, Democrat
W. Kerr Scott, Democrat
John Sparkman, Democrat
Olin D. Johnston, Democrat
Marion Price Daniel, Democrat
J.William Fulbright, Democrat
George A. Smathers Democrat
Spessard Lindsay Holland.Democrat
First announce which one's you'll do, so we don't duplicate effort.
MEMBERS OF THE UNITED STATES HOUSE OF REPRESENTATIVES
Alabama
Frank W. Boykin
George M. Grant
George W. Andrews
Kenneth A. Roberts
Albert Rains
Armistead I. Selden, Jr.
Carl Elliott
Robert E. Jones
George Huddleston, Jr.
Arkansas:
E.C. Gathings
Wilbur D. Mills
James W. Trimble
Oren Harris
Brooks Hays
W.F. Norrell.
Florida:
Charles E. Bennett
Robert L.F. Sikes
A.S. Herlong, Jr.
Paul G. Rogers
James A. Haley
D.R. Matthews.
Georgia:
Prince H. Preston
John L. Pilcher
E.L. Forrester
John James Flynt, Jr.
James C. Davis
Carl Vinson
Henderson Lanham
Iris F. Blitch
Phil M. Landrum
Paul Brown.
Louisiana:
F. Edward Hebert
Hale Boggs
Edwin E. Willis
Overton Brooks
Otto E. Passman
James H. Morrison
T. Ashton Thompson
George S. Long.
Mississippi:
Thomas G. Abernathy
Jamie L. Whitten
Frank E. Smith
John Bell Williams
Arthur Winstead
William M. Colmer.
North Carolina:
Herbert C. Bonner
L.H. Fountain
Graham A. Barden
Carl T. Durham
F. Ertel Carlyle
Hugh Q. Alexander
Woodrow W. Jones
George A. Shuford.
South Carolina:
L. Mendel Rivers
John J. Riley
W.J. Bryan Dorn
Robert T. Ashmore
James P. Richards
John L. McMillan.
Tennessee: James B. Frazier, Jr.
Tom Murray
Jere Cooper
Clifford Davis.