55ebird. Yes, even if you were not to upgrade the carburetor, upgrading the distributor is a wise move. Your original distributor is problematic by its design. Used original '57 'Bird distributors are going for ridiculous prices on eBay because '55 and '56 'Bird owners are seeking to eliminate their original LoadoMatic vacuum-only ignition advance distributors. Consider swapping out your original '55 'Bird unit for an aftermarket mechanical tach drive distributor with full centrifugal advance. Mallory has been making one for the 'Bird application.
Classic Auto Supply Co., Inc. aka CASCO, Coshocton, Ohio has a listing for one in their 2015 catalog. While I do not see it in CASCO's 2016 on-line catalog, there is a listing for their part number 12127M. Click the link below:
http://www.classictbird.com/Not cheap, but the Mallory unit will connect to your existing 'Bird tachometer with the Mallory supplied tachometer cable. Mallory's unit is mechanically better than your original FoMoCo distributor. The Mallory housing is billet 6061-T6 aluminum and the distributor shaft is hardened steel and center-less ground. The Mallory housing uses two self lubricating bronze bushings for shaft stability, and the distributor cap is GE Valox high impact plastic with copper inserts.
NOTE: Larry Evenson's 'Concours Parts and Accessories' in NV previously offered this same distributor. If you enter Concours' previous part number 12127-MK for the distributor or 12127-M for the replacement cable for the tachometer, Concours indicates 'call for availability'. Concours' contact number is 1-800-722-0009
Hope this helps.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York