348 battery

M8 i can't see that it matters just get the right size to fit the tray and then if the positive is on the wrong side just turn the battery round 180 degrees unless i am missing something

 

I just replaced mine yesterday 58R. (I have a '91, with the batt in the back). The positive post is in the outside, forward position.

The 58 R is a great size for the 348, because you can get it in and out from under the hood, without any dismantling. The hold-down bracket, however, is a little tight. I had to slide the battery rearward and up in the back, to get the bolt threaded. Once the bolt is secure, then slide it back forward and down, then tighten. Good luck!

 

FYI, for 1990 348 TS: Odyssey part number ODX-AGM34R

(10 year old threads and no part numbers)