Carb size questions l20b

[Joecey54]

So I have been thinking about putting some side drafts on my l20b.I have found a set of 40 webers with the manifold and also a set of clean 39mm street bike carbs and they are of course a lot cheaper. My questions are would that 1mm be noticeable and which setup would give me better throttle responce.  Im not going for a high hp l20 just something that runs good with a mild cam and header. And would be good for autox

 

Thanks

Joe

[datzenmike]

Then smaller is better. Bike carbs tend to be somewhat like SUs in that they are a constant velocity. This means that although the throttle may be full open the carb only opens for what is needed at low RPMs. Side drafts and bike carbs are better on a cammed motor that can use them. Of the both, bike carbs would be best but you still have to make a manifold.