Well, I guess I needed to do a bit of searching anyway.... but here's some numbers for you.....
STC Number: SA1-48
Description: Edo 249-2870 floats.
Status: Amended 01/01/1960
ACO: ANE-170 New York Aircraft Certification Office Tel: (516) 228-7300
STC Holder: Blakely James R
Address: P.O. Box 53 Westchester Station, Bronx, NY, US, 10461
Make -- Model (TC): Stinson Div. Consolidated -- 108-3 (A-767),
STC Number: SA74NW
Description: Installation of Edo 248-2440 floats.
Status: Reissued and Amended 08/01/2001
ACO: ANM-100S Seattle Aircraft Certification Office Tel: (425) 917-6400
STC Holder: Super Stinson Modifications, LLC
Address: 13173 S. Spangler Rd., Oregon City, OR, US, 97045
Make -- Model (TC): Stinson Div. Consolidated -- 108-2 (A-767), Stinson Div. Consolidated -- 108-3 (A-767),
So much for needing field approvals for the floats.
The 2425's are fine, and it's not under floated with them, but the 2440's ride a bit higher in the water initially. I do know for a fact that the bottom front skins are not the same.
An O470-R is 76 pounds heavier than a 6A-350-C1 Franklin....not quite 115 pounds, and the McCauley 2A34C is 4# heavier than the Hartzell HC-C2YF that's called out for in the Franklin STC, however the McCauley isn't plagued by the repetative inspections that the Hartzell is. Don't get me wrong...the 220 Franklin, as I stated earlier, is a great engine....until you need parts. As far as the O-470 eating jugs, that's 90% operator, and about 9% baffel seals and cooling system maintenance, we've found.
Most of the 0-470 conversions are moving their battery further back than specified in the STC and getting a field approved deviation for this. This seems to bring the CG in without having to add any permanent balast to the tail, and hasn't been tough to get approved so far. No matter what you do to an airplane, there's a "give and take" to it. Everyone that I know that has the bigger engines has been well satisfied with them.
John