Help on rebuilding a 73 340

back to balance - the 318 is internally balanced - no weights on harmonic damper or flexplate or torque converter. a 1973 340 with a 1973 crankshaft is externally balanced - the harmonic damper is counterweighted and the converter has counterweights on it. b & m makes a counterweighted flexplate for the 340, with it u can use the converter u have or any non weighted converter