Anything special about a 91 318?

Cuz the 500 is 904 based, and me +904s don't get along. Even though I don't drive them hard they don't last. 518 is 727 based, much beefier from the get go.
I've swapped several 727s where 904s came out and a few 518s in place of 500s over the years. 518 in place of 500 is even easier than 727 in place of 904.
Though "if" I could find one of those old smallblock to /6 adapters that 500 could find its way behind a /6 I have.