almega,
I bought one from Truck Shop, after they told me it did not interfere with the radio. It installed easily and worked fine but it was in the way of the radio. There does not seem to be an aftermarket electric wiper for the 54/55st that works with the original radio in place.
Also, some vendors say their aftermarket electric wipers work in either 6v or 12v systems and some list separate 6v and 12v wipers.
There was an original 6v 2-speed wiper as an option in 1954 (#320). These are not very common - Golden State Pickup Parts used to sell them when they could find them (at something like $150).
Tim
