Bruce

I think I saw this on the web before and answered it. Here is something else to think about.

A Cessna 175 is really a 172 that they put the geared O300 in. it is not a stronger airframe. The GO300 was not that much more powerful or heavy that it caused any problems.

I have a very nice 175 with the 220 Franklin in it. It is an exceptional airplane in all ways and I am very happy with it. I operate off a 1900' dirt/grass strip in Cheyenne Wy. alt 6100'. The plane has 4600 hours on it, 3600 under Franklins. Problem; I am lucky I can do owner assisted annuals under the watchful  supervision of my IA and in that respect go a lot further than is the usual on most annuals. This time I found the two lower hat section braces for the motor mount cracked. It took 4600 hours and the unfortunate added abuse of a dirt strip to do it, but if it can happen with the small weight increase of the Franklin it would I feel be more of a problem with the weight and hp of a 540.

It is repairable and not really going to be hard just time consuming.

Have a nice day.

Larry J.