A PAW .061 will turn an 8/4 with lots of thrust and throttle down very nicely. Diesels are great for flying with lower RPMs and less tip noise from the prop. You could put it in a Peck Polymers R/C Prairie Bird and have a nice relaxing plane to fly or an Ace 1/2A Wizard if you want a bit of a hotrod. A Goldberg Jr. Falcon with less dihedral and ailerons would be a good choice as well [ .pdf available for free here:
http://my.pclink.com/~dfritzke/ ].