[wrndln]

I agree with SeaSlugs, you better have a 12V negative ground system in your model A when you install the aftermarket wiper. Stock model A's have a 6v positive ground. Also, it appears the mounting of the wiper is going to be a real pain. The wiper from Mac's doesn't look anything like the wiper than came on a model A. 1928 model A coupes came with Owen-Dyneto (OD-C1) wipers that had mounting arms that fit in the holes in the windshield. The wiper wire is also a pain to install from the terminal box up the passenger side A pillar and across the top of the windshield. Grounding the wiper is also a problem sometimes, as only the power wire is connected to the wiper and the wiper relies on the chassis to provide the ground. I have a 28 model A coupe that has a OD-C1 wiper.
Rusty Nelson