1991 Chevrolet 1500 - battery size question

Had to replace my battery and at Auto Zone, they recommended a smaller size battery. Does the size make a difference?

If you mean the size difference by measuring the width, length and height no it does not matter . You can go to the AutoZone web site and enter your vehicle and see if what is listed for your vehicle matches your invoice then just drive on . Of course did you not ask Auto Zone this question ?

With batteries the most important measurement is cold cranking amps. How many you need depends partly on the size of your engine since it takes more juice to start a bigger engine. As long as the battery meets or exceeds the minimum spec for your truck, has the terminals in the right places, and fits the available space, you’ll be fine.

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See if this sounds familiar…

AZ: We don’t have your battery in stock. We have one that will work. It is a little smaller but it will work Ok.

Pablo: OK

They sold you what they had in stock. If it doesn’t start your truck when it is cold outside, they don’t care. They guy who sold it to you will not be there when you come back and complain. He’ll be at another AZ or another parts store chain.


Of course we might never know if Pablo is referring to the dimensions or the capacity of this mystery battery.

Or what the previous owner installed, they may have put the biggest battery in that would physically fit.

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Let me guess . . .

Your old battery was a group 78

And AutoZone recommended a group 75

I believe group 75 might indeed be the correct battery for the truck, but a 78 will fit with no modifications whatsoever, which is probably how you wound up with a 78 in the first place

And the guy behind the counter sold you a 75 . . . because according to their information, it’s what your truck is supposed to get

Am I even close . . . ?

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Autozone shows both group 75 and 78 batteries for this truck.

Lookups at ACDelco and Rockauto show only group 78 (or a 34/78).

This might be moot though, because we still don’t know if the OP was referring to physical size or electrical capacity.