I did a post of this in the glow engines forum. A couple of guys chimed in with some info, a few photos, and a link which has some history
on Ross engines and photos. I have a used Ross 61 as pictured in the link which is in real good shape. Got it off ebay around 2000.

http://modelenginenews.org/drj/ross4.html

That exhaust port is rather small but the Super Tigre X60 had what looked to be a small exhaust port also and it was a real screamer.
So this thing might be a screamer too. That K&B carb is one heavy chunk of metal and adding to the overall weight of the engine.
I would dump it and try a lager intake Perry carb to get the most out of the engine.


Glow Engines Forum - http://www.rcuniverse.com/forum/m_11518905/tm.htm