I’m at the point in my build that I need to purchase a new battery.
The old one was removed several years ago and I need to know the proper case size for a 73 big block so it fits properly with the oem hold down assembly.
I’ll probably get one at Costco and one with the highest cold cranking amps possible, but since I no longer have the old battery I don’t have one to compare it to.
I would think Costco can look it up, but I would like to go to a top post battery over a side post battery.
So basically going from a group size 78 (side post) to a group size 24 or 27 (top post).

Thanks in advance.

 

Can't help with the size but wanted to share some info. I needed a battery for my 2012 C6 and I came across an AC/Delco,, made in Germany AGM battery for about $200 at Summit. Best price I could find. I was actually surprised at the competitive price and the vendor. Would not have thought to look at Summit for a battery. And free shipping. Just a thought.

 

Look up a battery for a 1968 C3. All C3's in 1968 came with a top post battery.

 

I just replaced the battery in my son's BMW. I too got the battery from Summit Racing. It was an AC Delco group 49 AGM. They did added in a $6.95 oversize fee but still far less than any place local and no core charge. That battery was 58 pounds! I also needed to buy a specific BMW scanner to code and register the battery in order for the car to start and charge at a rate that's consistent with the battery's amp hour rating and the AGM construction after the battery replacement.

 

This has the dimensions but like you said I'd go to Costco....or Walmart..

https://www.oreillyauto.com/shop/b/m...uBUBpibEjY_R8c

 

The standard battery size for a 68 Corvette (group size 34) is really close to the size for a 73 (group size 78).
The 68 shows top post which is what I’m looking for in respect to the 73 which is side post.
Thanks Sunflower 1972!

 

 

The first battery I had to register was for my wife's Mini Cooper. It took some time to wrap my old brain around the concept, but an excuse to buy a new tool was I really needed to know.

 

nevermind...

 

Costco sells the Interstate Battery line and the prices are very Hard to beat....

My 1968 C3 came with a 427 and I have added new electrical items to the car so I wanted a battery that could tolerate the cooling down of my engine after shut down. I am running 12.25-1 compression and have an abundance of extra heat after shutting off the engine. I have two Spal Fans that run for up to 1/2 hour after shutdown and they push the heat out but present a formidable electrical load for a vehicle that is not running. For this reason I went with a Deep Cycling battery that fit perfectly inside the battery compartment. This battery can run electrical loads much easier than a starting battery can. This battery requires no special charging or anything, it just works and works well!

Using a gear drive starter on a high compression 427 made a huge difference in the way my car works. With the gear drive there is no "heat-soak" issues and the engine can crank fairly quickly even when hot. The electrical load on the battery is far less with the gear drive starter as well as it pulls a fraction of the current needed to start the engine. Instead of pulling 200 amps you can get away with 50 amps to do the job for you. The reduced electrical loads make it easier to use a small capacity battery if you needed to.

Many of the newer replacement batteries are available with dual posts on them. This is very handy as it provides a place for my EFI system to draw its power from. Having side posts can be a good thing but require the battery be well secured to prevent any problems with shorting out.

Before you use ANY new battery product you should charge it up completely and get it ready for going into service. This is very important if you want a long battery life. I also charge my batteries during the summer months to ensure they stay fully charged even though the car's alternator has been working. It is amazing how many vehicles keep their battery from ever being fully charged in the vehicle during normal usage.

 

I ran Marine deep cycle batteries in my drag boats with great results.
Can you provide the brand, and either the group size or the part number for what you are using?
Thanks!

 

The Deep cycle battery I am currently using was a private labeled battery and mine has a Car Quest label on it. It has a label that says: 24DC-1 and has a cold cranking rate of 550 Amps and a reserve capacity of 140 amps.

This battery fits in the battery compartment of a C3 very nicely.

 

I’ll check that battery out.
Thanks

 

Certainly true the more-modern, permanent-magnet starters draw & require less current than those starters relying on wire-wound field coils (e.g. direct-drive DR 10MT starters which are OE on all C3).

But, Not all gear-drive mini-starters have permanent magnets. Several designs have a gear-reduction drive But also have wire-wound field coils.

Some gear-drives are a series of gears which run slightly outboard of armature centerline. While other starters have an in-line planetary gear set (e.g. more-modern PG260 OE production mini starters aka PMGR that are GM standard since about mid-nineties).

A tell-tale sign of a starter with wire-wound field coils is presence of thru-screw(s) that're perpendicular to and countersunk-flush with outer surface of starter motor case. In many instances, the manufacturer (or marketer) covers those screws with label(s). But, you can usually "feel" them through the label. Those thru-screws pass thru the case and thread into a ferrous "pole shoe" which holds wire-wound field coil tightly to inside of case and clear of armature.

OTOH, typical permanent magnets are ceramic extrusions that're held tightly in place by thin spring-steel clips; NO thru-screws.

*liken the mini-starter array of offerings to a Hitchcock movie; things are often not as they may seem.

 

Here's a simple solution to use a side terminal battery - convert to a post with options

 

Thanks Richard!
Those are really nice.
I can’t make out the label, who manufactured those?

 

XS Power-

https://www.crutchfield.com/p_122555...apter-Kit.html

 

OldCarBum
I put this battery in my 68 a couple of months ago. May need to slot that rear mount sliding plate.
--Costco item number 1624514 refers to a Costco Interstate 24F STD battery.
It has a group size of 24F, 700 Cold Cranking Amps (CCA), 875 Cranking Amps (CA), 12 volts, and a reserve capacity of 130 minutes.
The battery is manufactured by Interstate, but sold under the Costco Kirkland Signature brand.

 

A large number of newer batteries are coming with both the Top Posts and the Side Terminals on them. They are electrically the same whether you draw from the top posts or the side terminals. Like many people, I take advantage of having both connected. My EFI system wants to have a "direct to battery" connection and it does on my car via the side terminals where I attach the Wiring. The top post's are still being used as in a normal 1968 C3 Corvette.

The Cold Cranking Amperage is more of an indicator of the heavier inter-cell connections that allow heavy starting current to be drawn at freezing temperatures. There are better ways to measure the batteries useful capacity than just CCA. I was running the testing of batteries of all types at my R&D lab where I would charge them to 105% and then remove/discharge 80% of their rated capacity. This allowed us to learn all sorts of neat stuff about how batteries work and which work better and those that who didn't meet their rated capacity.

Buy the Freshest Battery, (most recently made) battery that you can get. Buy a new battery at a store that sells a quadrillion batteries and you will likely get a fresh battery. The gas station down the road might have had their stock for months potentially sitting with a constant self discharge of 1-2% per day, not a big deal until you think about a brand new battery being left discharged for a month or more.
The batteries capacity can suffer if they are left partially charged for an extended period of time. Always charge them up to keep the full rated capacity.

ALWAYS Charge the new battery before putting it in the car. When I mention Fully charge a battery I am referring to charging a Flood Lead Acid battery to ~2.5 Volts per cell upon which time the battery should be gassing as it approaches the end of the charge. The gassing is there to de-stratify the electrolyte inside the battery. Gassing is normal for FLA batteries, you do not want to see your Absorbed Glass Mat battery gassing or the AGM battery gassing either.

The battery can be charged after installation but will be wired in and the heavy charge might affect the electronics by exposing them to potentially 16 volts or more. I prefer to charge the battery Fully while it is isolated from the vehicles electrical system.

Check your battery cables and eyeball the ground connection to be sure the connections are good. Battery Grease is conductive and it prevents oxidation on connections. The cables should be clean and tight to keep you smiling the rest of the summer.

Best regards,
Chris

 

Thanks guys!
I will definitely check into that Costco battery.

When I purchased my battery cables and connectors I purchased the Marine type that connect to the top posts and have threaded studs so I can connect additional electrical connections directly to the battery.
I also plan to install positive and ground terminals to tie anything else to.