Supposedly the AMC heads are a much better casting not prone to cracks (
tho they come with cheaper valves and retainers I gather ) .

I haven't seen any VW heads crack ....
I'd probably focus on that one if any problems tho.
Make sure your VW head, and both heads are  for a 2.1.

One 'rebuilt'  1.9 engine I ended up with had a 1.9 head on one side and
a 2.1 one on the other , until I got that straightened out.

If you personally don't know the exact history of what you have ..
you never know what you're going to find.   Could be anything.

Scott

On 6/18/2016 11:53 AM, Neil N wrote:
> On my 2.1 WBX, one head is an AMC brand the other isn't. The AMC head
> is on the passenger side.
>
> If one could determine which head has been replaced, can this narrow
> down which side of
> the engine to focus on?
> Or is a possible issue like a combustion leak between head and
> cylinder(s) still a 50/50 split between work done on newer head or
> parts on the older head and cylinder wearing out?
>
> Neil.
>
> On 6/18/16, Scott - IMAP <scottdaniel@turbovans.com> wrote:
>
>> For sure, residual pressure is not normal or a good sign at all.
>> Leak down test MIGHT reveal which side the problem is on ..'might' .
>>
>> or if wanting to keep it limited in scope for now ...if you can't
>> diagnose the problem to one side or the other, just do one head
>> carefully ..then see how it goes.  Most of the time that I've seen if
>> there is a problem on one side, it's the right head rather than the
>> left, fwiw.
>>
> --
> Neil n
>
> Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>
>
> 1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>
>
> 1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>
>
> Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>