Good point Stuart.

i jumped at the NR and YS recommendations because they are excellent and current. While the YS Classic is a short stroke (by request), the NR R61F is actually a long stroke. Both the high timed Speed and the lower timed non speed version. Either one seems to produce excellent output on larger props like 12x8 and 12x10 but the low timed NR might be best for the Desire.

There are of course some YS 61R and AR and OS 61 RF-P's around to be had as well designed for 12" or 13" props.

David