This is the lock button for vent windows for 356b t-6 and 356c models.
When the knurled end is turned in, the window is locked. it is a very difficult piece to replate, so we suggest this new part at less than replating costs.
644-542-559-06 vent window lock button, for 356b 356c 1960-1965
Many production cast iron and aluminum blocks suffer from a design weakness of cylinder stability by nature of poor support at the upper deck area. The manufacturing process of "cast in sleeves" provides for economy of scale in low horsepower engines, but does not accommodate high horsepower, high boost, or larger bore sizes. Darton has engineered a superior patented solution by using a unique designed cylinder sleeve which when siamesed and nested, creates a solid deck of sleeve flanges held in tension, reinforcing the upper deck area and provides for individual replacement with what they call modular integrated deck (mid).
In addition, darton designs' manage and enhance water flow from block to head ...(choose a part on the right to read more)