The distributor clamp is first loosely screwed/bolted into/onto the block - the clamp should be a little open/loose.
Then you install the distributor (through the clamp and into the block) as described in the Shop Manual? (with the rotor pointing to the appropriate spark plug?)
The distributor is lowered into the block, and into the oil pump (as described in the manual).
When the distributor shaft is seated into the oil pump, tighten the clamp screw.
