Stan,
The first question is: Why do you want to? It has me curious. I'm thinking that the engine/propeller combination on the Forney was pretty good and I wouldn't want to step "downhill" as it were. I'd guess that you could get FAA approval on a "one-time STC" (form 337) fairly easily by putting in the text that the airframe is essentially identical to the 415-C through 415-G which all fly just fine with the C-85. Ed Burkhead http://edburkhead.com ed -at- edburkhead???.com (change -at- to @ and remove "???")
