I said I had a 1979 Grand Fury too. Nope, I had a 1980 GF with E58. Slow car. Later platform- was M body. Had one of those pursuit vehicles too,1988 Diplomat, was much faster. Why aluminum manifold? Chrysler was in turmoil then (1979-1980) and eliminated the RB engines (for cars), so had big cars and small engines. Read - Slow Vehicle. They were trying improve performance, for cop car wise or Lil Red Truck, with this manifold, IMHO. Last LRT built, that I know of, May 1980.