I must have missed this thread. I have a Christen Eagle NIB (among a plethora of other ARFs waiting to get built) and I plan to put a Poulan 46cc on it. Mine is converted to CH Synchrospark and BCM Pitts and weighs right around 4lbs. Should fit entirely within the cowl except maybe the spark plug and the very top of the cylinder. Power is good - so far 7100rpm on a MA Classic 20x10 with about an hour total run time on the brand new engine. I would expect it to gain another 100-200rpm as it breaks in completely, but as is the Poulan 46cc should fly the CE just fine. Not 3D kind of power, but then I'm not a 3D kinda flyer.

To be fair, even though the Fuji 50 is roughly about the same displacement (46.5cc) as the Poulan 46cc, I was surprised that the Fuji is quite a bit more powerful and turns the same prop some 400-500rpms more. Perhaps the dual piston ring does help make more power. I am getting a Fuji 50 converted to CH Synchrospark and BCM Pitts for a friend of mine's GP 1/3 scale Pitts Special. Similarly equipped, the Fuji is about 1/2 lbs heavier than the Poulan. However, the Poulan still needs a set of motor mount so the difference is probably a little less.

I have the parts to put together another identical Poulan 46cc setup. That one will power the GP Patty Wagstaff. Poulan 46 is becoming one of my favorite midsize gassers - easy to convert, easy to mount, compact in size, parts readily available, cheap to replace, and makes good power.

Notice I said "cheap to replace". The replacement short block is cheap compared to a ready made gasser, but my setup cost total around $440:

Poulan 46cc - $130
CH Synchrospark conversion kit - $210
Bisson wrap around Pitts muffler - $100

You can go cheaper by staying magneto and/or using a less expensive muffler. Engine cost, of course, is variable depending on where you buy it. These days, I buy mine brand new from Lowes when it goes on sale and I have 10% off coupon. Just don't feel comfortable rolling the dice with refurbs any more.