Some years ago i talked with George Riehl from the "Chrysler 300 club" and he told me that a handful of '57 / 58 Imperial were fitted with the 300C/D induction system (2 x 4). But the 392 remains stock (no "three hundred" engine heavy duty parts as piston rings, camshaft, crankshaft, etc..). I think it was a "dealer installed" option. -- Philippe COURANT (Pau, France)- Webmaster des sites ACCF et C-I-F Imperial 1957 Crown convertible Buick 1958 Roadmaster sedan HT - American Car Club de France (ACCF) : http://www.accf.com - Chrysler Imperial France (C-I-F) : http://www.ifrance.com/c-i-f - Cadillac " Standard of Excellence " : http://www.ifrance.com/accf-cad - SportsCars : http://www.ifrance.com/accf-sprtcar