Originally Posted by Dragsix
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I did notice that he was unsure about the locating dowels on the head, and installed the intake without the rings. Maybe 216 motors don’t use the rings? Otherwise very enjoyable.
It looks like dowel/pin ("alignment pin") was used on each end of the head on Chevrolet 216/235/261 engines (GMC sixes used bolts):
Group 3.275

I'll bet that the rings ("sleeves") were also originally used on all years of 216/235 and probably all 261 engines (through 1963)?
Groop 3.291