Herb, The Ryobi 31cc was my first conversion, so I have a special fondness for it. Because of it's unique RIRE configuration, I'll always have at least one in my collection for those narrow cowl long nose airplanes like PT-19.

BTW, I sold my 42cc Poulan precisely because I didn't like the non-straight shot throttle cable hook-up. The Poulan 46 OTOH gives a straight shot parallel to the thrust line.