OK, now that the rest have stuffed in their "answers", here is the answer to the question you should have asked, except you aren't far enough along the learning curve to know the right question.

Any time you remove the crank, rods and pistons to build a stroker it doesn't matter what crank the engine started out with.

In nearly every case, the rods and pistons will weigh less than stock. And in most cases, the assembly will be able to be balanced internally, because the new crankshaft will have counterweights sufficiently large (heavy) to allow it.

Using an internally balanced assembly is preferable, if only for the fact that you can then bolt and unbolt neutral balanced harmonic dampers, flywheels and flexplate/torque converters without having to worry about balance. There is another consideration, but IMHO it doesn't really affect a street engine, one that is 1.5 hp/cubic inch or less. In cases wherte the engine is very high output, the rpm range is going to be quite high and in those cases an externally balanced assembly will put more bending stress on the crank and block.

This board is comprised of a bunch of old ladies, afraid of everything. The amount of external balance a 360 has is about 18 oz-inch. You'd think the engine would fly apart at first trip to redline, according to some. Yet, Ford 5.0s for years and years ran quite well with 50 oz-inch external balance. Other Fords did also. And the 5.0s or 302s did indeed split the crankcase right down the middle when they got enough over the 1.5 mark. That's with either power adder or rpm, IIRC. But that's with nearly 3 times the external balance amount as the maximum Mopar, the 360.

Now on to more mundane things. 1972 was a cusp year for Chrysler and so there are forged crank 400s and there are cast crank 400s. If it really matters to you, if you look on the Engine ID pad at top front of the engine, you should see some numbers and letters like H400Pxxxxxxx. H means 1972 model year car. IF there is also an "E" stamped on that pad, the engine came with a cast crank.

One last bit of information. Chrysler's inventory system wasn't the best, and they weren'[t building collector cars, they were building cars for people to buy and drive. So there are way too many examples to count of a part being where it really shouldn't be. One classic example is an engine with cylinder heads with different casting numbers, side to side.

Good luck with your build, and if you would like to PM me about anything, please feel free to.

R.