Jay Honeck wrote:
Petersen used to have a list of airframes tested and failed but I can't
find it.
You might email them. They do support some O-540 models (this is what
you have
right?) but the airframe isn't listed.


My O-540 is approved for car gas.

It's got to be the low-compression version to be eligible.

The PA-32-260 engine variant (E4B5 or whatever) is in Petersen's list as one of the 91
octane engines. However, the airframe isn't approved.