Apologies to raise this thread from the dead, but looking for information on 580003, which mentioned in each post of this thread.
Is it still with GM Heritage foundation?
https://bringatrailer.com/listing/19...omments-anchor
In this auction on BaT, the seller believes he has the engine from 5800003.
To me, the stamp looks like 5800008, but it's still an important piece, I would think.
Would love to hear others comments.