As for the stud idea, you don’t need to worry about alignment as there are alignment pins in the block to line up the oil pan . If I recall correctly, the bolts have a 13 mm head , so they should be 10 mm threads about 35 mm long the thread pitch should be 1 or 1.25

 

Thanx much pardner. Thank you all for the help and guidance. Happy New Year! :), Chuck

 

Wish, I could stop by and have a look for that lost oil pan bolt! It’s gotta be hiding somewhere!
A very prosperous New Years to you!

 

A telephone call to a GM parts department would very likely yield the specs and part number, maybe a good sob story would get it delivered at a reasonable price (less than an Uber ride).

 

I always read the OP's stuff. It took me a few minutes to do the reply and in the meantime he had posted again. That's why I didn't see it.

 

Ok, thank you.