<VV> Head Fins: How Smooth/Clean?

[JVHRoberts at aol.com]

This is one of the few cases where smoother is NOT better. In any heat  
exchanger, turbulence improved heat transfer. Even Porsche and motorcycle heads  
aren't smooth inside the fins. And for the same reasons. 
 
John
 
In a message dated 6/25/2005 12:54:19 PM Eastern Standard Time,  
pottsf at msn.com writes:

I have a  heat-challenged situation in my 66 Corsa 140hp that I like to run
with  stock distributor and ignition timing, and with stock shrouds. The car
is  air conditioned, and that, too, is stock (A/C condenser is upstream in
the  path of the air that cools the engine). I live in a hot climate, but  at
least I don't drive up long hills/mountains, and I don't pull a trailer.  If
I use regular gas, I get ferocious ping. Premium gets me by with about  zero
headroom on hot days.
I'm preparing a pair of  (stock) heads for use in this situation, and I
have just "deflashed" them.  Naturally, there remains a vestige of flashing
at the narrow point of every  through-passage, and I'm working on smoothing
these down (not easy, as  anyone who's tried it knows). I'm working on the
understanding (not  confirmed) that the closer I can get these flash vestiges
to disappearing,  the better my heads will be cooled. And this exercise
brings me to thoughts  about the REST of the cooling fins that the cooling
air passes over (the  parts upstream and downstream of the point where the
flashing is  found).
Obviously, the cleaner these fins are, the  better for cooling.
Obviously, these fins get dirty in use (I'm tempted to  spray coil-cleaning
chemical into the ductwork of my assembled engine). But  I'm still getting
them as clean as possible so that at least they start off  as effective as
possible.
My real question is,  should I bother to polish them (make them smooth)?
Could/should the FINISH  of the fins have any effect on their cooling
capacity, particularly after  said fins have acquired a patina of dust and/or
(shudder) oil or grease?  For the reasons described above, I need all the
efficiency I can  get.
If anyone has any actual experience to report  from, or solid
thermodynamic theory, I'd love to hear about it, preferably  in a POST to the
list. Thanks.