Looking for a new battery, 1970 Challenger RB 505 stroker about 12:1 compression that doesn’t get driven much, more of a strip car. Battery is located in the trunk, so weight is not much of a problem. What have you had good luck with?

RV/Marine group 27 deep cycle, Wal Mart or Costco

XSPower

I use a Odessey AGM battery in my 64 Savoy, installed in the trunk. It does not vent off sulfuric acid fumes like a conventional battery. I have it installed in an aluminum battery box. Still going strong after 7 years, keep it charged every other week. Cranks up my 505 with ease. Highly recommend. I also use 1/0 battery cables from the battery to the starter.

I haven't bought a new 'normal' battery in over 20 years, since I bought a couple of used 'gel-batteries' which blew the old stuff out of the water when it came to cranking power.

Currently using Exide Dual AGM.

YellowTop Optima is my recomendation

Whatever is on sale at the part store. Good amps, and better reserve amp minutes than anything you'll find from "racing batteries".

12v w/ good amps should turn over anything at 12:1 or else something else is wrong.

RV/Marine and Optimas don't seem to last long unless they're constantly being taxed, without an alternator, in my experiences. When I was a counterman during college, we would have Optimas of all colors coming back constantly from musclecar applications. My Marine battery lasted half a season in the racecar with an alternator, as I was told they're designed to be ran almost till dead and then recharged.

I have had good luck with the Carquest branded AGM battery. Strong cranking and good life so far..

I've had superior service from Optima red top batteries. I currently have 7 in use in my stuff including 2 in my racecar. I have 2 that are 16 yr old Blems that are still going strong. I've only had 1 red top go bad in the last 16 years. My recently acquired Optima charger says it can't be charged. That's what I'll continue to buy until they start causing me trouble.

My Yellow Top is 8 year old now, I run two fuel pumps, 2 fans, Electric pump, and Fuel Injection. I have made as many as 12 passes in one event and never worried about it. I do bring a spare with me on drag week but only because I am the GM at a battery distributor so its easy to grab a spare and take with me.

I have an XS (4 yrs old) in my dragster--Great battery so far--no special charger needed as all new chargers have AGM setting
But...
By far and away the best batteries I have ever owned are Interstate
I have a deep cycle Interstate I use in my camping trailer and swap it back to the race trailer to run the winch and it is almost 8 years old still as good as new
XS is a china made thing but has been great for starting a 14:1 engine in a very small compact package for reasonable price
I will never ever use anything but Interstates best unit in my personal vehicles

Pretty sure Interstate batteries are now different and not as reliable

Seems like the way of the world anymore

Cheap cowboy Boots $70
Good Lucchese boots $500
Really nice ones $$$$$$$$$$$$$$$

Last several batteries i have used i went into the Interstate store and bought. Never had issue one with any of them

After about 5 years of ongoing disappointments with over-the-counter batteries, and even worse experiences with the "reproductions", this worked for me...

An inexpensive battery that is rated well! I know a guy that bought a battery at Auto Zone and he brings it back every year and gets a new one for free.I bought an Exide for $65.Fires my Hemi at the hit of the key!

Never met a Optima yellow top I didnt like.

From Wikipedia:

Interstate Battery System of America, Inc., a.k.a. Interstate Batteries, is a privately owned company that markets automotive batteries manufactured by Exide Technologies, Johnson Controls and others through independent distributors.

Key words: Market, others.

I was a Parts Manager for 22 years and a counterman the entire 40 years of my career. In the 70's, mopar batteries were Johnson Controls. They were replaced by Exide. Exide was replaced by Interstate. Interstate brought their delivery system, thus eliminating facing PDC delivery. They all ebbed and flowed in quality. Exide took a hit, in the Sears fraud conviction.