As HotRod Lincoln pointed out, the Stovebolt rods are not what are ideal for this type of mod, but the GMC rods are, and can be swapped into the Stovebolt with little effort. Even though they do have just 4 mains, they have excellent bearing overlap between the journals and are a lot more rigid than people give them credit to be. A newer M90 Eaton blower might be a better alternative as they are much newer technology and less rotating mass and effort to spin. Unless your going after the nostalgia look.

We cannot solve our problems today using the same thinking we used when we created them!

Albert Einstein