One way is to flip the motor over and unbutton the pan. One of the crankshaft countrerweights has alphanumeric markings stamped on it's edge, and these markings identify whether it's a 429 or 460 crankshaft.

429 = 4U, 4UA or 4UAB

460 = 2Y, 2YA, 2YAB or 2YABC....or 3Y or 3YA.

Also, for quick identification of the crankshaft, you may look for the nodule or embossment between the first main journal and counterweight. The 460 is embossed there, while the 429 is not:

429


460


Paul