Re: visual differences between 3.9 and 4.0
The engine number will start with JG, and then a 2 digit number to identify the model, same as the VIN or chassis number. The 2 letters after this number identify the month and year of vehicle production. Post the engine number and I'll give you the date.
The engineering or casting number start with something like 87DA or 91DA, but is not a true reflection on the year of the vehicle.
Last edited by smally351; 09-19-05 at 08:41 AM.
Reason: added more info