[Formulabruce]

Wow pics!
Ya know, since the block was "Align" bored, I would FIRST get some new bearings and RE install Just your crank with lube and torque it down.
Then install the timing cover with a good front seal, and balancer . Don't need a chain. put small light near crank and see if you can see light at bottom side of your front seal shining on the balancer. Be tough to check the rear main seal this way with the width of the seal area.
( engine being upside down on the stand)
You MUST verify that the block will be able to run with No leaks.. You would not be happy to be back where this thread started, at a OIL Leak seal replacement.
IF ,and when, you rebuild this, or ANY Pontiac you MUST get it "Smoked"
Ask the machine shop for You to be PRESENT when the engine is smoked. You will see ANY and ALL possible Leak areas at the "smoking" session.
I have seen in person engines that were align bored and all assembled on the engine stand and FAILED a Smoke test....
Just hoping it turns out right on this build so you can enjoy it again.