I have a mostly stock 318 in my 86 Diplomat. The only mods are long tube headers and HEI ignition. Whenever I drive my car more than 20 minutes or so, enough to thoroughly "heat soak" it, I can shut off my engine, and if I immediately start it back I hear a knocking sound, much like spark knock, only while its cranking. It goes away immediately when the engine starts firing. There is never any knock while driving, and it never does it cold. Any ideas would be great!
