not sure what the battery holes are  like on the 85 but on my 82 the 
stock battery is a group 42 but a group 41 battery will fit in the hole 
with no modifications as well.  the 41 is longer than the 42 but same 
width and height.  if you want to use any battery other than those two 
sizes you will need to do some mods.  to put a bigger deep cycle in my 
aux hole i had to mod the back of the swivel on the drivers seat and 
then pin it so it doesnt swivel any more.  no loss as the drivers seat 
has the steering wheel in  the way when swiveling anyway.  
exide/everready/diehard  or any  quality battery will work.  the 
cheaper the battery you will note the lower the ratings.
jimt
On Monday, Sep 23, 2002, at 07:03 America/Denver, Joachim Preiss wrote:
> \ ...
> Can anybody recommend a certain brand and source? I checked ntb.com, 
> and they
> offer the DieHard WeatherHandler� North for $60, and the DieHard 
> International
> for $100. The web site doesn't tell me what Amp Hours the units have 
> which I
> am used to, only the Cold Cranking Amps, and they are 540 vs. 650.
> I am thinking about installing an auxiliary battery at the same time. 
> Should I
> use the identical type as the main battery, or something 'more 
> affordable'?
>
> Thanks!
>  Joachim
>