StrokerSix, I owe you a beer or poison of your choice! Because of your clue above, I think I figured out the WHY of this motor's head leak issue...
Thermal expansion.
The head is what, 30" long? (Don't have one here at work...!). It rises 140F in normal operation (60F to 200F, say, and that's assuming no overheating and impossibly even heating). The coefficient of expansion for cast iron is 5.8 microinches per inch, per degree F. That's .024" increase in head length! It cycles cold, hot, cold, hot, ... every time you drive the car.
We know for fact that on this motor the head gets hot (warms up) VERY FAST. The combustion chamber is over an inch deep in the head, with a lot of surface area (that oddball wedge). The exhaust passageways through the head are long.
Read this and watch the video:
http://www.boltscience.com/pages/vibloose.htm Plus, the head is heat-insulated from the block with the composite gasket (a copper gasket would be nice!). Therefore, the head grows more and faster than the block, by a big margin.
All this simply walks the bolts out. Because they are bolts [factory], they have a lot of torsional stress left on them; they are therefore predisposed to untwist to begin with. Add to that slowly crushing gaskets, too much or wrong lube (probably my problem) heat-softened, age- and overtightening-worn old bolts (probably my problem) just makes it easier and more likely to happen in 2010 than it did in 1963.
The head sealant goos simply lubricate the sliding.
* Head studs and the right lube will help a lot.
* Increased torque for ARP fasteners will help a little more.
* Extreme attention paid to head cooling issues!!
PRECISE LOCATING DOWELS. I'm gonna ask around about dowels. The differing head vs. block growth rates though means the head will try to shear them off the block. That obviously won't do.
