I have single-speed wipers on my 63.
What do I need to switch to multi-speed wipers?
Can I swap just the motor and switch, or do I need to replace everything?

Motor, switch and the sandwich of parts that connects the motor crankpin to the wiper linkage. It is different for the variable speed wipers, and using the single speed setup's simple nylon bushing does not allow the wipers to park correctly. Remember the 1963 A-body wiper motors are one-year-only.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I missed the class on windshield wipers.
I thought 63-65 wipers were the same.
Did they make any variable speed wipers with the small (1/4")
pivot post?
What years will fit in a 63?

Is there a article somwhere describing the different years for types of wipers and interchangeability?

Firewall on 63 A body is one year only, it was changed for '64 to accommodate 273 V8 engine (which does not fit in 63 A body without firewall mods). As result, wiper motor mount and therefore motor itself was changed. Not sure about linkage, some pieces may be the same.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.