Hi, it is going to be hard to keep up with all that is going on here now, I know that none of us are going to puposely ignore any one. I just received the 8mm x 1 taps I ordered so now I can make a couple of prop hubs. I have an engine like you describe, designed with a 2 bbl carburetor and an engine like Dave Wallace's, designed with a single bbl carburetor. I kind of like these carbs, IF they will perform. No one has mentioned the original carbs that I have seen. I will "open ports" also if needed. I have mine cleaned up, the back plate mounts made, and when I get the hubs machined, I am going to test them against each other, with no porting and the original carbs for a baseline(s) of operation for these Toros. It is good to hear the report on RPMs that you are getting and I agree they are well made engines. They are nice and light also as you say. It looks like they have a forged conn rod besides the dual reasonably sized front and rear bearings. The 2 bbl version also has a 3/8" spark plug (3/8 x 24 threads, I think, they are fine threads, but I really didn't think to check until now. Normally you find a 7/16" thread on trimmer spark plugs. Oh yes, the reason I want to run them with the original carbs is because I ran them as a trimmer powerhead, as received, and the throttle response was excellent, nice and lively, but of course there was no load. The Toro carbs I discussed are not like a Walbro or a ZAMA and in fact are somewhat like the rotary barrel RC engine carbs. The idle adjustment that is more important to us than a weedeater user is accomplished by a mechanical limit stop of the rotation of the rotary barrel, cylinder, or whatever it is actually called. The single barreled carb is somewhat simpler, simply by having only one bore through the carb that the rotary part opens and closes like a RC carb. The bore on the single bbl does seem small and could be restrictive. The 2 bores of the 2 bbl carb also seem small. In spite of this I will try them and might work on them if necessary because I figure if they won't work as is, there is not much of a gamble in possibly ruining them. I have already figured how to lighten the spring return so a servo would not have to fight a fairly strong return spring. Some carbs are a challenge in figuring out a linkage for them that will be good and reliable. They all seem to be different in some way so expect to put on your thinking cap for this part of any conversion. So, has anyone tried a converted engine with the original Toro carb and what were the results? A new carb and the cost for it to get the most performance out of any engine is likely to be the same for these Toros as with most other engines I suspect. You at least need to have a 2 needle carb for RC. Most trimmers I see now have a single needle carb.)