RE: OS 32 SX Aircraft engine
The OS32 was not ringed. They were a very strong, long running engine. It would be hard to find one in new condition. The viper wont hardly care in terms of flight flight characteristics whether you hang a 25 or the new Evolution 60 NX on the nose. The only difference of course would be speed and fuel consumption. Do see the threads about strength mods for the Viper. Don't spin up a starter motor than slam it into spinner to start. You will break off the firewall as the starter wobbles about the spinner! That's number one cause. Back the prop off compression, center the starter cone then push the switch.