Continuing the dialogue with David Schwarze:

> >Heads can be interchanged between 1800s and 2000s (1800 valves are bigger) but 
> >1700 heads only fit 1700s. 
> 
> Nope.  I took a set of heads from a 1700 in the junkyard and bolted them
> right down on my 1800 engine.  I'm pretty sure they had not been flycut.
> 
 This is good news, the info. I gave is from a magazine article I read some
 time ago (but still have, if anyone is interested)

> > 			So, to make a displacement jump from a 1700 you have
> > to change everything but the case to get to two liters, and change barrels, 
> > pistons and heads to get to 1800 (the best of the bunch, in my opinion).
> 
> Again, you don't have to change heads to go from 1.7 to 1.8.  The most you
> will have to do is have the heads flycut, but I don't think so.  I also
> am almost positive that you can make a 1.8 into a 2-liter by using 2 liter
> pistons, barrels, rods, and crank.  You can even cut down the old 1.8 liter
> crank to a 2 liter one.  My source for this is "How to rebuild your Air-
> Cooled VW Engine", and numerous discussions with machine-shop guys.
> 
 I think you are correct here as well, though I have heard little anecdotes
 about but some special hardening or other treatment on the 2 liter cranks to
 offset the reduced journal size. Does anyone have any factual info on this?

> My ultimate plan is this:
> 
> '73 1.7 heads, flycut if necessary for 94mm barrels.
> 	(74 heads not used becuase of egr ports)
> '74 (larger) valves, sodium-filled for the exhaust
> 2-liter crank, rods, pistons, and liners
> 1.8 cam with solid lifters (apparently hydraulic lifters have a different
> 	cam profile, less power).
> 
> This should make a powerful, cool-running 2-liter engine which to the
> untrained eye (i.e. smog mechanics) will be indistinguishable from the
> stock 1.7 engine.
> 
> 
> 
  I spoke on the phone with the proprieter of Stephens Machine in Tehachapi, CA
  (a type IV cylinder head outfit) and he says he routinely plugs the air
  injection ports without ill effects. For your ultimate engine, you may want
  to consider the heads from a 2 liter 914 - they have the biggest valves of
  any type IV motor.

  By the way, I'm interested in knowing whether Sodium cooled valves are worth
  the extra money. My own experience is good - I have 104,000 miles on a 1.8 
  liter that has never had it's heads off. But that's not to say it wouldn't 
  have gone that far with regular valves. Does anyone have more specific 
  experience? The sodium filled valves are about fifty bucks apiece compared
  to $8 or $9 for standard.

  Dave Kautz