BTW, Terry is right about it being part of the fun of converting engines. In fact, I'm so impressed with how several of my smaller conversion motors run on WT-499 and glow fuel, I had Terry order me 3 more of them Walbro critters.
I will say this though, 31cc or 2 c.i. is about as big a glow conversion I would do anyways. Much bigger than that, then the sheer bulk of the glow fuel you've got to carry in the plane starts to work against any power gain you might realize. Plus at 40cc and up, the power to weight ratio of most gassers starts to become very competitive with glow setups.