I want to know where the top of the fill mark is on a 62 olds Starfire power steering pump

 

The " full " mark is on the neck of the reservoir .
The level should be checked when the fluid is warm , and filled with Dexron III ATF .

 

I’ve put NAPA power steering fluid in the reservoir, did I make a mistake?

 

If you just topped it off , you're OK .
A complete drain and fill should be ATF .

 

I don't think power steering fluid would be a problem at all, they all are just a high grade type of hydraulic jack fluid. Most of the better parts of the ATF aren't used or needed for the function of the power steering parts in my opinion and that opinion it's worth what you paid for it.... Tedd

 

Power steering fluid should work fine, like Tedd says, its just hyd fluid. I fill those to the base of the neck.