Rob,
When you say "E" designation for engine, do you mean that is the engine code within the VIN, or the suffix in the engine serial number? I don't think there is an E by itself as an engine serial number suffix, but I did find reference to a VIN-E code pertaining to the 427 truck engine.
Lookie here for a list of the suffixes for the 366 and 427 truck engines. Note the VIN codes in the comment column.
