The $250 reproduction sealed battery that I had in my 65GS is finally dead an won't take a charge. I had to take the battery out of the 64 Skylark and put in the GS to start it up and move it last weekend. With the dead repro battery and the modern day AC delco battery sitting there side by side, an idea hit me.
I figured out that the threads on the Delco caps from the reproduction battery are 7/8-9. The battery is junk, so I decided to put the caps to good use.
I pried the two 3-gang caps off the top of the 24PS AC Delco battery and tapped all 6 of the holes in the top of the battery with a 7/8-9 tap. The important thing here is to keep the tap perfectly straight as it goes in so that the caps seal flush on top of the battery. Also make sure you have on some clothes that it won't matter if you get a dash of battery acid on since the tap will be dipping into the acid as it goes in. You can get most of the plastic shavings out with needle nose pliers, but if you can't get them all it is no big deal since it is just plastic chips floating in the acid. Be sure to wash the tap and any tools that get in the acid with water as quickly as possible and put some oil on them.
In case you don't have a dead reproduction battery to pilfer the caps from, there are people selling the caps on ebay and the reproduction battery companies will also sell you a set of caps.
I then took a small flexible hand saw I have that is made for intricate wood working and cut the handle bosses off the side of the battery so that the side is flat like an original (or at least looks that way when viewed from the top). Finally I removed the decal from the top and cleaned the goo off with some carb cleaner.
Once in the car, it looks like an original to the majority of people and even some that know the difference if they just glance at it.
