A group 42 is actually a smaller battery. The Diesel battery will not fit under the seat. If the stack size battery does not get you going then you most likely are stuck anyway. An engine starting battery will not provide long term service for cycling applications. This has been somewhat hashed to death. 

Dennis 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Loren Busch
Sent: Wednesday, February 10, 2010 10:58 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Best battery

On Wed, Feb 10, 2010 at 6:40 AM, Doug Alcock <doug.alcock@gmail.com> wrote:

> For size you want a "Group 44" battery..........
>

Actually the stock battery size in both battery compartments in a Vanagon is
a Group 41.  A Group 42 or 48 will also fit but are smaller.  And some use a
Group 91