I've got a 2-piece prop and was wondering how much clearance I should leave around the front section? It is bolted solidly to the engine at one end and enters the centre-bearing at the other, so I guess the only movements are due to the engine cradle bushes and/or any flex in the centre-bearing.

Reason is I am considering placing the actuator unit for my electronic shifter (Kliktronic) down in the tunnel, parallel to the prop and need to know how much room I should leave between it and the prop? Or should I not go this route?

Here's a piccie of me holding the unit in the approximate position (with prop suspended in it's normal location) - it lies about 2-3cm from prop:

As the front section of the prop is only going to move a couple of mm, I'd say 20-30mm is fine.

Pat...

Should be fine, if the prop starts moving that amount then you have other things to worry about