rat,
My 261 with Fenton exhaust and Offenhauser intake has two one-barrel Rochesters on it. After running it without a heated intake for two years, and experiencing hestitation at low revs, I installed a heating plate (water from the cooling system) from Tom Langdon's Stovebolt Engine Co. and it runs much smoother.
Are you heating your intake? I understand that it might be warm where you are (I dream of being warm at this time of the year) but the intake can get quite cold from latent heat of vaporization (I think that is what it is called). Supposedlly, an unheated intake can get so cold that it can cause the vaporized gas to recondense inside the manifold - this could result in a properly tuned set of carbs running rich at times.
Tim
