If you must single-handedly roll back 10 years of emissions control technology, then do it all the way. Remove [b]everything[/b] related to the emissions, including replacing the carburetor. I was selling parts for a while, and this dude came in returning his 3d carb. "I need to return this POS" he says. "It ain't right." "Really?", I ask, painfully aware of the statistical improbability of 3 bad identical parts in a row. "It just won't run right, no matter what I do. I've put ball bearings in all of the vacuum lines, disconnected all the wires, ran regular gas through it, I mean I did [i]everything[/i] to that truck, but it still won't run right. What a POS."
One brave soul against hundreds of engineers spending thousands upon thousands of hours, and he doesn't understand why "it just don't run right."
If your truck runs well as is, why fuck with it? Your mileage won't go up that much, if at all, and trees don't do shit for NOx and HC emission.
Just leave it alone.