There's plenty of space....
There is not room on the passenger side in my van for a bigger battery, not counting the tray. Not the same engine compartment as a 6.9!
Cubey, your van is the 74-91 Body. The other two fellas have a 92+ body. Big difference in under hood space. We had an 85, and a 94. There was acres of room under the 91 down hood compared to the 92+ The IDI's take up most of the room. I don't see how they put the 6.0 in the vans......
Ah, I see. I misunderstood. Are they in sigs? I've been on mobile today, where sigs don't show up.
Yeah, the 1992 engine bay is a little different. It seems a bit more narrow on the passenger side. The group 31 barely fits. No way a group 65 sitting there.
Regardless of size, NEVER, parallel different amp hour or chemistry batteries if you want long life from them. Not done anywhere else by EV vehicles, drones, battle bots, boats, planes, off grid, etc. Even if battery connections balanced, the smaller one will charge and discharge faster with indicated voltage the same.