I couldn't find a number tack welded on my chassis, but juding from every one elses number, I am willing to bet that the chassis number is the same as the Engine Number. For those of us who have the original window stiker of our ds the Engine number is lower than the VIN number, and If I am correct the Engine number is the number that designates where your d was on the production line. If you have Engine # 5404 then your d was the 5404th d out of the factory. Am I correct? Joe P. VIN 6808 Engine 5321