[dmsfrr]

Examples of two differences between the '57/'59 Y-block distributors and the '59+ versions. There may be other/later versions but I haven't looked into it.

The '57/'59 distributors use a vacuum diaphragm with a straight actuating arm. The points & condenser are mounted on a round plate that rotates on small ball bearings in a groove around its perimeter.

The '59+ distributors have a curved arm from the vacuum canister. The points & condenser mount to a smaller plate that pivots on a pin opposite the wiper of the points. (photo 3, red arrow)
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