I have to agree (and disagree) with Bigedmustafa. Some castor is good for the bushed engines, but 10% nitro, 20% oil (half synthetic, half castor) is ideal for an LA engine.

I'm running a 12-4 master airscrew on my LA .46, on Sig Champion 10% nitro, and it runs like a dream. Nice low idle, good torque. It surely doesn't scream, but it pulls my Pete'n'poke aound like a 4-stroke.

Phil