TOM, tell me what it's worth and if I agree I will buy it from you if you want to sell it.

bigben,
1. I have several planes set up for the Brison. I need that backplate mount and side induction. Any other configuration would require a major rebuild.
2. I'm from the old school and I like the mechanical advance over the electronic because of its fast response.
3. I don't need the power of the newer engines. My planes are already over powered. I would rather have the reliabilty of the Brisons.
4. The standoffs introduce a very long cantilever from the firewall. I've seen those engines vibrating a significant amount as the piston bangs away perpendiculalar to the standoffs. You can't beat keeping the pistons close to the firwall for a secure and vibration free system.
5. I'm not a big fan of those rear input diaphragms. It's another moving part I have to worry about if the engine does not start or run poorly. I would rather have the carburetor get its input pulse directly.

That's enough. I'll have to change over one of these days. I can live with the OS 55 layout. Like everything else with OS it's expensive. A spare ignition module is $250. A carburetor is $150. Maybe one of these days. Not right now.

Dan.