Well...  Let me tell you all a story...

We had the dreaded stripped exhaust bolt hole syndrome on our '83.
Top #4.  Tried JB Weld, Tried 271 Loctite.  Tried a helicoil. It would
hold for about ten minutes then loosen right up again. Last year I
disassembled the back end of the motor.  Exhaust system, thermostat
housing, etc. so that I could see what was what.

Now mind you, I have a v. complete tool box.  Includes an industrial
pneumatic right angle drill with screw in bits.  I have bits that can
make it possible to drill with about an inch and a quarter space.  I
tried for two days to make that drill fit so I could drill a STRAIGHT
hole.  It just wasn't going to happen.  So the van sat.  For a year.
(I needed to cogitate on it...)  Got myself another head (Thanks
Karl!) just in case.

Fast forward to a couple three weeks ago.

Went back out and looked the situation over one more time.  Motor
in... man, what a PIA.  Motor out... easy.  So I bit the bullet and
dropped the motor.  Straight shot at the hole.  Took my electric B&D
3/8" drill and opend up the hole to 17/64.  Bought a M12x1.25 tap.
Threaded the STRAIGHT hole and screwed in a Keen-sert.  Did the
unstripped hole too.  Just 'cause it was right there.  Put new M8x1.25
studs in.  Bolted it all back together. and raised it back into the
engine bay. (Didn't take it OUT, just lowered it on the jack.)  Total
time... about 6-7 hours.  After it sat for a year because I was too
stubborn to do it the easy way.

It might be possible to do it in situ, but taking it out made it
worlds easier.  Total cost?  $4.26 times 2 for Keen-serts.  $8.76 for
tap.  As opposed to $300+ for a  replacement head.

Save yourself the agravation.  Drop the motor and do it right. If you
get the hole crooked, you really have a problem!

As always... YMMV.

Jim Arnott
WetWesties
Union, OR