Here is mine. I choose to cut the top off, and gut it. Also cut treads in the old post from under side and put post. But can do a bolt washer. Had the extra post and cables so just tried them.
Rubbed the box down with Red Weneol and then wax looks better than new
I also had some plastic angle so epoxied it on so the lid would stay put.

http://s234.photobucket.com/user/fast340six/slideshow/Battery
Here is 2 other members here Batts one is done from under other is done from top
http://s234.photobucket.com/user/fast340six/slideshow/Battery2

Hack saw. Yes just the hack with fine teeth, and did it slow.
Did do a quite a few fill drains with stuff to neutralize the acid {baking powder and something else as well}
Inside is lead plates on a card board type sheet. So comes out ok but is dirty.
It is by no means a clean job but is easy
I do smelt 1000-2000 pounds of lead a year. I cast lead thingys as a hobby. Lead is OK with me but acid is not
But tossed this stuff properly since it is bad news.
Inside cleaned well. Is so clean now i use it as a prop and a real battery to drove / move car
In fact the pictures is taken in the living room.
When I did asked the wife to grab the battery so i could shoot some. She brought it to me lol Great when ya marry the right gal.
Sure is light easy and clean, and can have a battery in it to work as one is minutes.
Best would be to use The cables other way than I have them!
{IE} Bolt and washer to old post on underside of old post. Make sure when you cut it you leave enough to get the post flat on underside. That way you get a good tight fit! Cut it long and then cut a second time flat. Get it flat, so you can thread it and have enough for washers and bolt. That's why I cut top off, and not bottom method.
Note} I Used the cables the way I did since.
1) I had the 2 adapters for side post battery here new in pack. As well as the Cables 2} The Battery I was using had top post terminals
I could have used the cables the other way. But did nit since had a different battery connections on the battery it self. Best would be Bolt and Washer threw cable to under side of old battery terminal, and a threw bolt and washer with nut on battery terminal post. As they make battery's that have that type terminals.
Like used on a Lawn and Garden ones

I have a restoration battery that has bit the dust. I don't know if these are even available, but I'm tired of paying the price for these and having them only last a a few years.

Someone posted a how to of gutting a restoration battery and putting an Optima battery inside. I've looked but can't find it.

Does anyone have a link to this? Would be a big help.

Thanks!

How big of a space do you have available inside the case? There is some pretty stout AGM motorcycle batteries that might do the trick, you might be able to fit two of them in there to boost the CCA.

The battery that people seem to have used is the Odyssey PC 295, but on one of the moparts posts I was pointed at, someone said that the battery would not start his 440-6 when it was hot.
...................................................................................................................................................................................................................................................................
I have the same set up of 6PKRTSE (PC 925 Odyssey)
Never had hot cranking problems a 451 cid 11.25 cr

SPECIFICATIONS
Pulse (5-second) Hot Cranking Amps (PHCA) 900
Cold Cranking Amps (CCA) 330
20Hr Nominal Capacity (Ah) 28
Reserve Capacity Minutes 52
Dimensions L x W x H (in) 6.64 x 7.05 x 5.04
Metric Dimensions L x W x H (mm) 168.6 x 179 x 128
Weight (lbs) 28
Weight (kg) 11.8

here was mine.