maurtis- I read your thread- interesting- but you never reported how it ran!
I would think the bigger intake and matched port would do quite a lot. Is it the newer 66 Speed carb?
Sounds like you are wanting better carburetion?
So yours has the wider spacing but still the smaller motor mounts?
I noticed the bigger difference on my older 66 simply when I went to the billet first- and the original NT 50 carb was on for awhile- then I put the Speed carb on for another slighter improvement. But the first billet took out all the bogging down. (I've had a slight problem lately that started about the time I put this ultra-small two dollar filter in line- Think I have to go back slightly larger there.)
Anyway the 40 mm billets are $20 and shipping I think- maybe you should just try that first.
Never mind- when I look at the ads, you'd OBVIOUSLY need the other CNS billet if you eventually go that route. Or use their adapter- same dif tho I think. Unless you just want to gamble for the other cost- shipping has gone up- I got my first billet for iunder $15 a few years back, them another one later on for half off- I think about $12 shipped. I'm not sure what the total cost would be now- more like 30 I guess - too bad.