This is likely similiar to the missing post ,
Marv Gingrich "1978 C body wiper cam parts. Over the years there have been many posts about wipers on 1978 New Yorkers. I along with many others were confused about what parts fit our cars. The proper parts have not been available for years. I did find NOS parts that shattered trying to install them but was able to reproduce them with better and thicker material. These only fit 1978 cars with 2 speed wipers with intermittent feature.
This eliminates the need to find an older donar car and cut and weld to repair 1978 wipers. Please note you need to use your old spring. Interested? email, marv.gingrich@gmail.com