One word of advice before doing the JB weld treatment is to take your heads
down to a local machine shop and have them pressure tested.  This will save
you having to go through all the trouble and then a year or 6 months later
you start leaking compression into the coolant.
If they test OK then do the JB weld thing.  I wouldn't smooth the edge where
the big black seal attaches to the head too much.  You want a little
coarseness here to help give the head glue something to grip.
I would also clean up the case and JB weld any pits in it (where the head
gaskets seals around it).
Have fun and if you find you do need new heads please give me a call as I
have a good price on new heads right now and also engine gasket kits for $99
with both sealants in them.

Hope this helps,
Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242