Here are pics of my HB.
Just putting the correct balancer and flywheel on will not guarantee that the vibration is gone. The only sure way to have everything that came on that motor was to find an original, untouched engine and trans or own it since new and drove it yourself to know that it was balanced. Getting the right stuff "should" balance it out. If not, you have to have a machine shop do it. You would just have to take them all of the pistons, rods, pins, rod bearings, crank, balancer and flywheel. That is why it is worth the money to have it done while apart.
If you want to verify that you have a cast crank, look at the parting lines between the rod's journals. If it is a skinny line, it is cast. If it is about 3/8" wide, it is a forged crank. You better check that because some 72 340s were forged.