Double nutting will work just fine.  Wear and tear on the threads in the heads is a non issues unless you plan on removing and installing the exhaust system often.  Another good option if you want total security, install M8 x 1.25 x 16.2 Time Serts in all eight threaded holes.  Use 8X35 SS bolts instead of 8x30, they will get a much better connection.  Use Anti-Sieze on the bolt threads.  

On 2012-04-30, at 5:46 PM, Automatic digest processor wrote:

> I'm interested in hangining my exhaust in an all-bolts configuration on the
> rebuilt 2.1 I have going into my 1.9 van.  I plan to use a4 stainless 8x30
> bolts.
> 
> (My reasons are: it seems both studs and bolts have benefits, but they are
> maximized running all-studs or all-bolts.  E.g., with all-studs, none of
> the holes have thread-wear, with all-bolts, you can do a head gasket
> without removing exhaust.  All-studs are not an option for me since the 1.9
> water pump is in the way of removing the headers when using all-studs.)
> 
> My plan is to remove the studs was just to tighten two nuts against each
> other on each stud and use that to twist it off.  I'm guessing that this
> should be easy since the heads (and studs) are brand new.  Do I need to use
> a stud puller instead?  Or should they come out easy with the double-nut?

Cheers,    

Frank Condelli
Almonte, Ontario, Canada
'87 VW Westy, '00 Kawasaki 250 Sherpa, "98 Ducati 750 Monster & Lionel Trains (Collection for sale)
Frank Condelli & Associates - Vanagon/Vanagon Westfalia Service in the Ottawa Valley
Vanagon Stainless Steel Exhaust Systems
BusFusion a VW Camper camping event, Almonte, ON, June 07 ~ 10, 2012