Hey Ragz.

I'm running an OS .50SX on my OMP Edge540P. Same size and weight (1/2 oz heavier) as the 46FX just a little more kick. Turning an APC 12x4 it's a rocket ship. I was running a MACS pipe, but switched back to the stock muffler...no big change, maybe a couple hundred RPMs.

You want this plane as light as possible, but with enough power. The 46FX has more than enough power. With the 46FX installed the CG is just right without adding anything, moving the battery around in the radio compartment allows for fine tuning. Installing a 7oz heavier engine will mean even more weight in the tail to get the CG right...just a thought. I'm sure the plane will fly good with the extra 1lbs from the OS70 and weight in the tail, but it will fly AWESOME without it!!!

I recommend the 46FX...

-DRW