18N368587 (18N36?587) - L78 engine

[1971z28]

396ci/375hp motor with matching heads and aluminum intake.

T1207MQ   18N36 8 587
(fourth digit "8" between 6 and 5 is very faint, could be a 3, or 6?)

Casting numbers/dates:
Heads
   GM3T 3919840 Hi Perf K  3 o 7
   GM4T 3919840 Hi Perf A11 o 8
4 bolt Block
   Truck Pass A Hi Perf 3916323 L4 o 7
Intake 3933163

[KurtS]

Thanks for posting.
After seeing the pad picture, I think the faint digit is either a  3 or a 5. So 8N363587 or 8N365587.

Nothing in the database on any of those VIN variations.