change a 180 O360 to a O540

[70GV]

I have a 1959 180, I restored this plane from cone tip to tail, wing tip to wing tip. I did the work myself with my IA's constant review.
My self imposed rule was if I touched it, it could only be replaced if as good as new or better. EVERYTHING!!!!
this plane has a true fire wall forward overhaul
Time and money were not a factor in decision making if to replace or repair a system.
Mistakes were made in my log book and the FAA required me to bring the plane to them for inspection, after 3 hours of 2 FAA reps. crawling all over her it passed with flying colors. and they commented that it was one of the nicest restorations they've seen.
154 since new prop and western skyway overhaul.

I had a 210 for decades and logged over 3000 hr. in her, and flew the 180 after 18 months and over 90K investment I found it to be anemic in power. I fly in the California Sierras, On a warm day I cant fly her from my airport.
Now for the question.
I want to convert it to a O540. Is there a STC for this or do I need to do a 337 I have a timed out engine already out of my sons 1960 250. I've researched the mechanics of the change and it's pretty straight forward.

Greg

[LeWayne Garrison]

Don't know of an STC. I do know of a person in Colorado trying to convert his 180 to a 250 via a field approval. Been trying for years to get it through the Denver FSDO and no luck so far. Not even allowed to fly it as an experimental. Other FSDO's might be more accomodating.

[Don Ostergard]

I am aware of two 180's here in Western Canada that have been converted to 250's - one at least 40 years ago, the other about 30 years ago. Each was done as a one-off approval from Transport Canada. Unfortunately, both fellows have departed on their final flights so I can't ask them about any details. But they did manage to get TC's blessing on this which pretty much means that anything is possible.
Don Ostergard ICS 3263

[Michael Bryant]

This has the info you are looking for: