R59 Delco Battery
 

Does anyone know how high to fill one of these batteries up correctly without overfilling them?

I would do about a 1/4" above the plates.

Ok thank you

be mindful that these real batteries with acid like to vent and do a number on your paint. monitor closely!

OK thank you again for all the help.

I seem to recall instructions (from a long time ago) that said to fill to the bottom of the "split ring", which I believe is the bottom of the "neck" in each cell under the cap.

That is correct, and make sure it is fully charged if topping off.
Mike

I would take the battery out during long storage...

Yes it seems to be holding up fine now. I can't believe their was no water in it.

Dennis,

Go to your local NAPA store and buy a battery filling jug. Has a spring loaded filling spout that you insert into the round opening on the top of the battery and press down to fill. Fills to the proper level every time. Costs < $10. Use only distilled water and you will be a happy camper.