The 2s venuii that I've seen have all been mounted 8 o'clock to put the muffler in the tunnel on the bottom of the fuse. Most of the cutting was to get the head out of the side. I guess you could mount it pure inverted with minimal cutting for the head, but then you'd have to cut some for muffler clearance. Inverted engines can be more difficult to run b/c the fuel / oil can settle to the bottom and foul the plug. It's really a matter of preference, but for that reason, I'd probably do the 8 o'clock thing. I haven't seen one purely side mounted yet. HTH, Chuck