hi gyra im just guessing but with 40 inch tall tires and 950 cfm carbs u have a couple things out of wack with each other. it is common for folks to have tooo much carb, that is too much fuel. i will venture to say that 1 of those 450 carbs would be nearly enough for your ride,considering that the rear gear ratio is probably sky hi. u could try a set of shorter tires if u doubt what im saying here. hope i didnt make u mad caose i could be wrong but i have seen this same type of engine-eering before. anyhow let us know if this helps any. Ives