Hi all just purchased a 71 340 this past week and need help id'ing the motor I cant find the id pad with the VIN unless its the one on d/s below head. I am thinking my motor is not oe to my car and depending on if its the original is how I restore it.

The manifold is 3512100 (intake) which is correct for 71 340 but if im reading the pad correctly the block is a 68?? so im lost please help

http://s892.beta.photobucket.com/use.../library/Mopar

2780930 340 LA 1968-733512100 340-4 (68-73)
DW34023860400 (?????)

I also can find exhaust manifold castings where do I look?