Yes that does make sense. I am remembering something about the early 1.5 blocks with 11mm headbolts suffering from cracks around the bolt holes.
More progress:
Chased/cleaned the bolt holes
Cleaned up the block deck. I really like that super scraper.
Cleaned up the piston tops and measured piston protrusion with a small stout straightedge and feeler gauges:
#1 .026
#2 .016
#3 .034
#4 .032
#5 .034
#6 .032
What's up with outlier #2? No signs of valve collision on piston top.
Looks like I go with 2-notch head gasket, here are the specs:
mm (in)
0.81-0.90 (0.032-0.035) 2-notch
0.91-1.02 (0.036-0.040) 3-notch
It had a 3-notch replacement gasket. I think repair shops commonly replaced head gaskets w/ 3-notch across the board. Easier to stock one gasket version, and no having to measure/ no chance for valve interference. The tradeoff is lower performance.
Here are photos of the piston tops. Can anyone decipher the markings?
P1020688.JPG
P1020689.JPG