I've been watching this thread with much interest... the '71 1600dp I 
just finished rebuilding came to me with nothing related to a 
thermostat.  I went ahead and rebuilt it anyway, without one, then 
cringed after reading Bob Hoovers sermonette about the reduction of life 
without one.  Not only don't I have a thermostat, the heat risers (tubes 
going from the exhaust pipes to the intake manifold) are cut off and 
welded shut!  The last guy to work on this engine was quite the butcher!
Anyway, here's the questions in my mind:  

So it will reduce the life of the engine... How Much?  Will I only get 
100K instead of 150K miles?

Living in N. Florida, am I not STILL better of that somebody in Minnesota 
that HAS a thermostat?

Being the rookie wish-I-was-a-good-vw-mechanic, I probably have other 
factors that will shorten my engine life more than the lack of a 
thermostat, don't I?

Putting in a thermostat is an engine-out job, isn't it?

How many of you would put one in at this point?

Signed,
Don't make me do it... :-)