Try Tractor Supply or any farm implement dealer. I know TSC has 6volt batteries, don't know if they're maintenance free.

Thank you guys, really appreciate. could some one explain to me about 800CCA and 900amps, are they good enough to crank start? Please advice.
Thank You agian

Use heavy gauge cable between the battery and starter as-well as your grounds most of the newer 12v cables are too small .

batteries can be somewhat confoooosing with all the numbers.... a high CCA rating may not be the best selection... as most high CCA batteries don't have much reserve... so.. you can pull lots of amps to start.. but leave your headlights on for 15min,, and the battery is dead...

if you use the lowest CCA rating.. that will give you a high reserve battery,,, so it will start well.. and allow you to leave the lights or radio on for much longer..
it also is easier on the internals of the battery,, and they tend to last longer.

this may not apply to aftermarket high torque starters.. as they need AMPS to spin them...

when it comes to 6v systems... there is a bit of contact resistance that can become a pain,,, as you can loose a volt or 2 getting to the device... so BIGGER wires.. and BETTER connections are mandatory.

I spend a couple hrs every spring .. and clean terminal connections at battery,, and starter, and headlights so they will operate well for a year.

Golf carts use 6v batteries... and they are very common... but they are rated using the reserve capacity of Ah ... so a 210Ah battery is very good... where as a 100Ah is lower....... all stock engines I have worked with will work fine with 150Ah

Another battery was mfg'd to compensate for some line loss , and high resistance connections... and it has an additional cell... making it an 8 V battery.

some folks really like the service from an 8v the only drawback if it fits in the battery tray

recently I was trying to source a few batteries that had tight specs... and I had endless bad advice from "pro's" selling batteries that turned out to be very oriented towards the battery with the highest price tag being the best.

When you throw in the terminal locations, and CCA and reserve numbers.. there is a myriad of choices in a book...

I found that Costco and TSC had top notch batteries on for under $100 sale prices... 25percent more list ..... and they were not their GOLD battery,, but bronze

Canadian Tire was an endless hoops and hurdles to just buy a battery... they kept telling me the battery would not fit and they could not sell it to me.. altho they did not know what does fit the car .... too old for their catalog... sigh
when a manager finally allowed me to buy it ,, with a VOID warranty.... I had a second thought.... and asked that battery be tested before I take it outside the store....
it failed! .... so did the next 3... and then I found they had date stamps .... so I searched the shelf and found a new stock... and it tested fine.

Do you have a battery store near you,, most will help you out... put in any battery that fits.. and they can measure the cranking amps of you engine... then you will know if 200 CCA is adequate... or 600 is required
As it is a Chrysler.. they tend to spin over many more times than a chev... so I would get low CCA so the battery has more reserve for sure..

www.batteriesinaflash.com/golf-cart-utility-batteries/trojan-t-875-8v-170ah-flooded-lead-acid-gc8-deep-cycle-battery

if you go in knowing some info... like dimensions.. and terminal post type and location.. and you can buy it for $100,, vs $300.. they you will know when you are getting BS from the sales.. and go to another vendor.. up to you..

google "BCI group number GC2 "
www.batterystuff.com/kb/tools/bci-battery-group-sizes.html