I think they could easily be switched, though... I have a GXV120, GXV160 & GCV190 that would all be suitable for either application. The blade brakes come right off the shaft, and there's just a lead with a bullet plug coming from the coil to connect to the on/off switch or bail mechanism.
Right now, I have
two GCV160s that were pulled from blade brake clutch mowers. They were the original engines on the AYP-built mowers mentioned
here and
here
Both engines have compression and I got one of them to run. The problem is that they both have a cable-actuated choke system that's controlled by the throttle lever, and the throttle lever was was dodgy on both, so I couldn't set and unset the choke reliably.
Ultimately, I ended up yanking the engines+clutch systems on both mowers. One of the mowers received a newer GCV160 that has a bail mechanism and a fixed throttle (it's also about 6 years newer than the rest of the mower):
The other remaining mower is slated to receive a Tecumseh engine from a recently junked Toro that's also configured for a bail setup, I'm just waiting for a suitable bail to be delivered from ebay. I already had a suitable brake cable.
As for converting those leftover engines with an on/off switch or bail use, it could probably be done, but not at a reasonable cost. It'd be far easier and cheaper for me to get entire mowers for free that already have the bail setup.
