[olddog]

If you already had the crank ballanced with those rods, you might as well stick with them. If you switch to H beam rods you will have to have the crank reballanced for the lighter rods.

You really should have the complete rotating assembly, including ballancer and flywheel all together when it is ballanced.

From what I have read, those rods are plenty strong, but a little heavy for high rpm work. Although back in the day, it is claimed that they ran them at 7000 rpm all day long.