From a little reading, I think I'm okay replacing my battery with another stock battery, but I do plan on beginning my 5.0 swap with my tax return this coming spring, and don't want to have to buy another different battery with the swap.

Since I am replacing the battery anyway, is there a size code for Miatas that I should look to up the CCA? In my current 5.0 Mustang, I've had 0ga wire leading to a battery with about 1,000 cca, but the battery is larger than what would go in the Miata.

 

I just bought one of these: http://www.summitracing.com/parts/ul...-164/overview/. They did a price match at a much lower price for me from another supplier.

 

$0.02...DieHard Gold AGM. I've seen too many Optimas die easy (see what I did there? ) in off road vehicles that see limited use, extended store time, and then heavy current pull from winches. Most these are running V8s also. When the Optima in my Miata dies (came with it), I'll definitely go to Sears. That said, my Optima is 4 years old and works flawlessly. ...so there is that....

 

I used a Miata-spec battery for two summers with my 5.0L. Restarts when the engine was fully warmed up were a bit tough so I replaced it with a normal sized battery. I don't remember the specs however.

So yes, you can use the smaller battery but if you are buying a new one anyway, get one for a full-sized car.

Also, make sure you get a PM starter from a later mustang rather than the older starter (with separate solenoid) from an 87-93 Mustang. I used the Miata battery with the old starter at first and I could not start the engine when hot.

 

Welcome to the forum! Thinking ahead like this is going to serve you very well with your build.

It really doesn't take a special battery for the V8. I'm using an ATV battery that will fit in the palm of your hand on an LS1 car and it works just fine. That being said if I was to buy a battery today it would be this one.

 

It's interesting, the three recommended AGM batteries in this thread are all the standard size for an early Miata, but there is a world of difference in their cranking output. The Marathon is 400 CCA, the Sears is 600, and the Optima is 720. That's a big difference.

 

My Optima is larger than a standard Miata battery. It lasted 8 years & probably would have lasted even longer if I had decided to plug in the Battery Tender or driven the car some.. The car has been sitting since January & only driven twice since March 2013.

 

Optima® 8020 164 Redtop® Starting AGM Battery 35 Top Posts Only | eBay

 

Wow I did know there was that much different in the CCAs on those batteries. Anyone know if the 5.0s take more grunt to turn over than the GM LS engines?

I ask because this is what I used in my donor Camaro and my Miata over the last 4 years.
Product Code : ETX16
Voltage (V) : 12
10 (AH) Capacity Rating : 19
CCA @ 0° F : 325
Length : 6 7/8
Width : 4
Height: 6 1/8"
Weight: 17 lbs

I've never had any trouble with it but I know I can't leave the radio on all day and expect it to start either. I never looked to notice the Marathon only had 75 CCAs more. I just figured it was the right size sealed AGM, gets out of the park reviews and is cheap so I never questioned the HP of the thing.

Oh and to be clear I am not suggesting anyone run the tiny battery I am now. The only reason I am using it is it's half the price of the right way to do it and going from 40 lb normal battery to 17 on the nose of a Camaro is worth not being able to run your radio all day.

 

When I get home this evening I'll poke my head in the trunk and see what size it is. I don't believe its a standard size for a Miata though as the carpet trip was relocated with new snaps. FM told me they have swapped to 'Vette batteries.

 

I would assume so since everyone knows Fords make more power than Chevies. (Don't try to confuse me with the facts; my mind is made up)!

I'd be curious to hear any experiences in recent years with the Optima Red Top. Optima moved production from the USA to Mexico in 2009 and complaints about Optima batteries have since soared. Tbone, yours still kickin'?

This battery makes the best CCA I have seen and also has big reserve power; just wondering about reliability.

 

LOL you always crack me up sunshine! Except when you write a book that makes me think too hard...

If those dogone red tops didn't cost so blasted much I could see it but all those ccas just don't get you to 60 any faster.

 

True that.

You've exposed my ulterior motive. I'm looking at upgrading the sound system in my car. With only a stock 5.0L in there, after adding a couple of RockFord Fosgate amps I'm afraid if I turn up the volume the engine will die.

Since my wife likes music, I'm thinking I can justify the new heads, cam, intake, throttle body, and MAF as necessary to power the upgraded stereo. Oh, and buy a battery so it works as promised.

 

The first one lasted 11 years. It probably would have lasted longer if I had installed a Battery Tender or at least started the car every 6 months or so.