Block 53021319AC...
earlier this year I had one brought to me that was bored to 4.055,that was built as a "6.1" another I had bored to 4.055 that was stroked and built as a 426. the 3rd AC block I have here that was bored 4.055 is a back up for my own build.
the 4th AC block I have here is bored to 4.03, for my niece.
Block 53021319AG....I have 2 here that I wouldn't take over 3.96 and still feel safe. I have another 4 that I haven't sonic checked yet.
Block53021319CB, have 2 and neither has been sonic checked.

stock 3.917 bore and oversized (2.18) Intake valve Apache, needs a bore notch.
STD Apache Intake Valve , and the 3.917 bore, could use some notching if your going gonzo power build.