Those are more common. The true 60-61 GMC used a bag and a foot lever pump. THe one withthe button in the middle of the switch 'I think" were for the 2 speed wiper set up fo a later model year. Link a photo and the guys will know right away what years and series.

I was looking for the floor verson. I'm cheating now by useing a generic one I found off eBay.

1960 GMC 305A V-6 Gallery Page
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