427 gm airplane block

[P.J.]

time to change subject.
The original owner of my factory ordered 68 Camaro L78 black on black m22 488s.
worked at the time for GM as a enjineere. He as on the team that was developing the NASCAR motor. He told me that GM
gave him several 427 BLOCKs to try out in my 68 Camaro that were made for aircraft. This block was thicker walled than the regular 427.(Ran cooler).<he also told me that some of these blocks got out onto the production line and gave GM much trouble. Has anybody ever heard of this happening??
I Know that this guy is a respected drag racing legend
in Winsor Ontario.
PJ