Im having the same issue with my 3 port spec R, it has a weak bottom. It has about 1.5 gallons thrue it and i cant seem to get the bottom to come alive. Just like he said, right when the midrange kicks in it takes off like a bat outa hell and has a screaming top end. I have the clutch set-up for more bottom, I have ran an 086, jp-3, and an 053 for pipes. The 053 had the most grunt, but it still was nothing like my 5 port or my sport 3 port. It runs good, at my last race, no flames in three 6 min quals and a 35 min main. It also like to run a little cooler than I like, but it still has quite a bit of pinch so that mite change. Im going to throw a nova carb on it today and see how it likes that. I know they changed the crank on these motors for a smoother bottom, so maybe thats it. Are you guys running the spec 3 port motor experiencing a weaker bottom on these motors???