Click on image for the lowdown. 
====
| | | Forums66 Topics128,180 Posts1,057,153 Members48,464 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Feb 2011 Posts: 6 'Bolter | | 'Bolter Joined: Feb 2011 Posts: 6 | Dear all, Does anybody know the dimensions of the original battery box on a 3100 1949 model? I need to buy a new 6volt batterie and would like the biggest cold crank amp as possible but I am not where the truck is at and dont have any body to measure. Thats why I would like to know the dimensions to fit the biggest batterie.
Thanks for your help!!
| | | | | Joined: May 2015 Posts: 11,159 Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums | | Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums Joined: May 2015 Posts: 11,159 | The Optima website has a thingy that lets you check fit. It lists your vehicle in the choices and even goes back into the 1800's, which is pretty surprising, although they say they dont' have a battery that will fit a 1898 Duryea or a 1929 Ford Model A. In my experience, the 6V for my Model A was the same size as the one for my '51 Chevy. 
Kevin 1951 Chevy 3100 work truckFollow this saga in Project JournalPhotos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together. | | | | | Joined: Feb 2011 Posts: 6 'Bolter | | 'Bolter Joined: Feb 2011 Posts: 6 | Great! Thanks for your quick replies and help!! | | | | | Joined: Apr 2008 Posts: 899 'Bolter | | 'Bolter Joined: Apr 2008 Posts: 899 | Would the felt rings be needed on an Optima battery since it's not a lead acid battery? I've also read that NO-OX ID is also a good conductive grease.
Ed
| | | | | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | Ed,
Yes, NO-OX ID is a good choice: " . . is an electrically conductive grease that keeps metals free from rust and corrosion . . . "
I suggested the felt rings for use as an "insulator" between the battery posts and the battery cover. The Optima battery placed diagonally in the battery box fits snugly/securely under the the battery top retainer (link given in a post above), but the posts are a little close to the edges of that retainer. Put the inexpensive insulators above the retainer on the battery posts as a cheap, and probably unneeded, "insulator".
The 6v battery box size on 47-55st trucks was designed for the very commonly used Group Size 1.
| | | | | Joined: Feb 2001 Posts: 4,095 'Bolter | | 'Bolter Joined: Feb 2001 Posts: 4,095 | Optimas are initially more money but I had one in my 54 for 13 years and it did not fail but was getting weaker so I replaced it before going to KC for the truck show. Auto Zone sells a similar one made by Penn called a Platiumn that is a gel and a little cheaper. I know they have 12v but I am not sure about 6volt.
Ron, The Computer Greek I love therefore I am.1954 3100 Chevy truckIn the Gallery 2017 Buick Encore See more pix1960 MGA Roadster Sold 7/18/2017
| | | | | Joined: May 2001 Posts: 1,907 'Bolter | | 'Bolter Joined: May 2001 Posts: 1,907 | Optima still uses lead acid chemistry but with a very different internal structure (and higher purity lead). I suspect picking one up would verify that. 1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
| | | | | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | | | | | | Joined: Oct 2018 Posts: 59 Chief Bottle Washer | | Chief Bottle Washer Joined: Oct 2018 Posts: 59 | Tim,
Thanks for the info on the battery group...It's the first thing my supply guy asked me, is what "group" my old 6 volt was...
Jim | | |
| |