Biggest battery

[crusty]

Getting time for a new battery.  Can't find solid information of what the factory size is.  All the parts store look up guides list multiple sizes, some are drastically different.  From what I can tell, I have the bigger factory 27F.  Just wondering if there is a bigger battery that will fit without modification?  Not going to modify anything.  I know that if I am willing to change battery cables, make new hold downs, etc. I can stuff just about anything in there.  Not doing that.  Just the biggest drop in is all I am after.  Only worried about the BCI number at the moment, I can shop around for which brand once I find if there is anything larger than stock.   

[radin2son]

3+ years ago, I replaced  the starter battery and was asked “long or short?” Long fit the battery tray, so I went with the technically described “long.”  
 

This past May, I replaced the battery with AGM battery. Shorter than the battery tray, technically speaking. 
 

Given your Crusty nature () took a photo this morning of the AGM battery I bought from O’Reilly. Hope this helps. 

Edited July 29 by radin2son

[WanderlustAV]

Still a 27F but a nice upgrade all around.  Cost a pretty penny but worth it with a discount.  4yr warranty, real high CCA and low risk of draining the starter when parked with the dome lights or radio on, etc.   I have one of these in a diesel and it'll cold start that engine in -40 F using a momentary glow plug switch. 

 

Only annoyance with these X2 batteries are the terminal posts.  The posts just seem extra tapered and slick compared to normal batteries. They are high quality brass but, because of this I guess, never seem to get along with factory clamps.  Not the worst thing as most factory terminal clamps could use an upgrade anyways. I typically go with marine style. 

[WanderlustAV]

Had to cut off the factory nut for the flimsy oem terminal clamp and trim the plastic cover but have a marine style clamp now.

[crusty]

Just got mine.  Not installed yet.  See how it goes for me.