EJM wrote:....Maybe like the guy that claimed to have the axe George Washington used to chop down the cherry tree,
I only has seven new handles and three new heads

It's exactly like that.
Unless you can find an IO470-S replacement engine,
overhauling George's ax might be more time- and cost-effective than jumping through a bunch of approval hoops
and /or doing a bunch of modifications to whatever you do find.