Loc: Brookshire, Texas, USA
Not only will the Engine require an STC, the airframe must be STC'd also to make it "legal", at least that is how it is here in the States. There are a couple of conversions in the works I found online that are using the General Motors LS series V-8 engines, perhaps if these obtain an STC soon, this might be a more efficient way to go. Vesta (www.vestav8.com) makes a chain driven re-drive and propellor system that fits on inline, V-6 and V-8 engines. I noticed you are located in Indonesia and since I am not aware of the flight rules for there, perhaps you can get a field approval for the auto engine. Also check out www.quietaviation.com
It appears you're out of luck. In any case, a lot of folks with MoGas STCs are having trouble right now finding fuel without ethanol in it. Some report luck at marinas, but fuel on the lake is often almost as expensive as 100LL.
Q.I have an 0-320-H2AD, why isn't this engine approved?
A. This engine is slightly higher in compression than the other 160hp 0-320 models that were tested. Therefore a test program only applicable to the H model would be necessary. There are not enough of them to justify the cost of these tests.
I had done the research previously and found what you posted above. I had a glimmer of hope though when Nightowl posted. I'm hoping he jumps back on here and clarifies if there is something I am missing!
I was hoping that with the demise of the 100LL in the future that companies like Peterson would re-consider the detonation testing on the H2AD. I have no idea how many are left flying with that engine.