O like the idea of gravel better than the chain. When you say date code you talking about th 1 letter 3 digit code on the driver's side? If so that is j139. There is another number on the passenger side but I don't think it's a date code. It is 9799916 or 09799916. I threw in pics of those, also a pic if the carburetor. I'm wondering if it came with the new engine. I've also thrown in a couple of mystery pictures. One is inside the trunk. I'm guessing possibly an add on air ride system and the other is a set of wires attached to the drivers side wheel well with only the black wire grounded to the throttle cable bracket. Don't know where the others are supposed to go but the other side of that box says MAGNA PULSE.