I see that
STC SA360EA cannot be used for just any Cessna 170B; it is restricted to N9047A. That aircraft has been deregistered but the last owner's address can be found
here. Might be worth writing the owner on the off chance they still have the paperwork. Also check out N388TC, a C-172 with a 180 HP Franklin. It would be a long shot, but
Franklin Aircraft Engines might be able to help.
For what it's worth we have a copy of N3843V's STC for installing a 6A-355-B Franklin on a C-170
A #075 here — unfortunately there are no installation instructions included. It's
STC SA1048NW.