Yes basically instead of two fuel circuits on an S&S it would now have 3. Intermidate jet from idle to 2500 then main jet from 2500-4500 and the Thunderjet from 4500-6500. My current carb is jetted to run hard at full 6500rpm but when cruising at 3500 she a tad rich and runs a touch rough. If I jet to cruise smoothe she's lean and pinging up top. This means it needs a more linear fuel ratio and cannot be tuned out. By adding the third circuit it will fix this and fuel curve will be more linear across the rpm band.Does the T-jet really narrow the band the other jets are responsible for. From what I've read at their website in the past the T-jet doesn't do much of anything at all until at least 4500 rpm. Did I read that wrong? I don't spend much time at all in that RPM range. Has anyone here ever installed one and felt any honest increase in their midrange.