Okay, the 16x8 props came in. This morning I ran the engine on a 16x8 Xoar. I was able to get 6650 rpm with the DLE30 carb and 6800 with the DLE20 carb. Still somewhat below the 7400 rpm listed in the prop range for this engine. I'm going to leave the DLE20 carb on it from now on.

So, again I'm taking av8tor's advice and sent an email to Frank Bowman to ask if he has a ring for a First Place Engine 1.3 It could be that this engine is just tired and maybe a new ring will perk it up a bit. If that doesn't work I'll try once more with a 16x6 prop and just live with whatever it gives.