Got it! Located an original, pressed in the new bushings which were available from NAPA, and am happy. The arm on the original was not debossed with an engineering number, just a faint debossed "188 " near the center link end of the arm. The pinched end was still intact on the stationary end threads so I am sure the arm had never been changed. The cost of the bushings was $26.00 if anyone is interested. Thanks to all for the help, that had been an elusive part. Jeff is correct, the idler arm is one of the first items to be replaced and even a trashed original is somewhat difficult to find. Looked over a pile of at least fifty at Mustang Corrall in Edwardsville, Il before finding a candidate for a rebuild. $20.00 for the core and an hour of sorting out arms to find the correct one.