Wolf_n_Kat -
This is an educated guess ...
Chassis VIN = B30CA4Snnnnnn
The first two characters might also be C3. The third character could be a 9 instead of 0 (zero). The fourth character might be a B if your vehicle has a lighter suspension. The fifth character might be a D if your vehicle has a 440-1 instead of a 440-3. The six character would be a 3 if you have a '73 chassis. (Or a 2 if it's a '72 chassis but that's fairly uncommon.) The seventh character could be a T, depending upon which plant built the chassis. The last six characters (eighth through thirteenth characters, shown as nnnnnn above) is the individual serial number for your vehicle.
If the fifth character is an N, P, or R, you have a 413 CID engine which, in my opinion, is a better engine than the 440. (My '72 M375 has a 413 engine and it tried to lift the front wheels off the ground when I goosed it while going 50 mph.)
