If you are a) broke or b) building an AMC or any other make that has no inexpensive aftermarket stroker crankshafts available, try the rod stroke trick. For about $250, a good machine shop can give you any rod journal size you'd like. Offset-grinding the journal adds stroke. The 401 rod journal was turned from 2.248 to 1.880, making the final stroke 3.934. Add that to the 4.210 bore and you get 438 inches.