OK, I've looked all over trying to determine what is so special about the WT-499s other than they are used on Zenoahs. Converting to glow with a WT-324. Venturis are the same so I wonder if the jetting is different. I checked Walbro's site and I didn't find specifics. Anyone know how good a WT-324 is? It came off a Poulan chainsaw so I would imagine it would have to flow a fair amount of fuel to run a 16 in saw. It has a high and low speed needle so I'm not quite understanding why it wouldn't be able to be adjusted in. I read a good thread about a Ryobi with a WT-499 converted to glow. Any Walbro experts?