Interesting Weber jetting

[jimf]

These were recently purchased (the 40's) as well as the complete conversion set up with the 37's in it. Both the 37 and the 40 are very much out of round with different bumps and hollows on the internal surfaces. This is to say when measuring with a inside micrometer. Yes I would agree that if you polished them up they would appear to be quite nice as I did polish one up before turning them. The thing is when you put them in a lath and dial them up you would see how far out of wack they really are to each other. I was very suprized to see the variation from one to the other in size. I can see how they could have produced very different results from one cylinder to the other if I would have used them the way they where. I am a bit of a fanatic when it comes to making everything identical from one cylinder to the other. This is why I choose to machine the bore so that they are all exactly the same. I guess I will try to use the 41.5's and hope they are not too big.