Jim,
I just did this on my 84 300SD. I used the Victor Reinz headgasket.
Elring has also been recommended. I cleaned out all the bolt holes first
and used a 12mm x 1.75 tap to chase all the bolt holes. I sprayed a light
oil on the bolts before tightening. You have the right sequence?

Step 1 40Nm
Step 2 70Nm
wait 10 min
Step3 90*
Step4 90*

Two tips:
Grind the heads off two of your old bolts and insert them into a bolt
hole at each end. That helps you guide the head down correctly.

After you do the first two steps mark each bolt in the same spot with
some paint or fingernail polish. That helps with the two last angle torques
getting the angles right and not losing your place in the sequence. (tip from Dogguy)

Also don't open up your head gasket until right before you install it.

Have Fun,
Jeff

__________________
1984 300SD 300,000 miles--two tank WVO setup
2.88 diff & 500SEL anti-squat rear end