The parts book shows the intake manifold has two part numbers. ECU 9424 A calls out as used in '56 and ECU 9424 C used in '56-'57 The only notation is that the C uses a 3/8" heat indicator bulb, whatever that is. Where is it? Is that why there are two styles of crankcase intake air filters, one taller than the other?

A friend has a '57 and swears he can't close his hood with the stock air cleaner on. He claims his manifold as too tall. I believed only the carb changed, not the manifold. I suggested he look at the motor mounts.

Your thoughts?