Weber 40 IDA 3bbl jet starting point for a 2.7 /6 Options

[tornik550]

I have a freshly built 2.7l with 9.5:1 compression pistons. I currently have zenith 40 tin carbs with 34mm venturi's. The engine runs very well however I stumbled upon a nice set of weber 40 IDA's. I am much more familiar with weber carbs so I purchased them.

What would a good starting point for the following be?

venturis
idle jets
main jets
emulsion tubes
air correction jets

Also, are weber idf jets and vents interchangable with 3BBL IDA's?


Thank you

[JmuRiz]

I plan on running an O2 sensor in mine too, gives full rev range info to help with setup.
Got a bung installed on my headers and everything.

Question: will just one sensor bung work, or does it need to be on each bank (I'd guess one is fine)

[Mark Henry]

I plan on running an O2 sensor in mine too, gives full rev range info to help with setup.
Got a bung installed on my headers and everything.

Question: will just one sensor bung work, or does it need to be on each bank (I'd guess one is fine)

I'd just run one in the muffler, you could put a bung in each side and just swap them.
One per cylinder doesn't make much sense, are you going to jet one side different than the other?
Or the other extreme every cylinder has different jetting?

If you are getting this much variance then there's likely something mechanically wrong with your engine or at least your linkage.

BTW badly adjusted linkage is the first thing I look for with carb tuning issues.