Parts that are occasionally neglected are the pieces that make up the coke heater system. The 1956/57 models have a tube inside the cross over exhaust ports of the intake manifold which burns out. In some cases, the owner is unaware of a problem until the choke is completely inoperative due to being packed with exhaust carbon.
Shown is the 1957 type. The cross over tube P/N 9890 is the same for both years. The 57 model has a mushroom button which acts as an air filter on the drivers side of the engine P/N 9492, this is the intake necessary for the carburator vacuun to circulate heated air to operate the choke. The 56 model has brass fitting P/N 9877 and tube P/N 9820 that draws filtered air from the carburetor. On the passenger side of the engine is brass fitting P/N 9884 same for both years and a tube and fitting P/N 9819 as well as an insulator P/N 9865 which are slightly different on the two-year models.
In order to replace the cross over tube the intake manofold must be removed. The tube is usually burned in half. The two halfs can be punched to the center of the manifold then removed. The average mechanic can complete this job in an hour.