[William]

The #6 ZL1 hammered for $650,000 last spring, a Cortez Silver automatic. Restored, known history, OE drivetrain, never raced. One school of thought, automatics [22] are rarer than 4-speeds. We'll see.

ZL1s are no different than any other muscle car. The original engine makes the car more desirable and valuable. In addition to the usual casting date and VIN stamp, ZL1 blocks were cast and machined in sequence. You could have an NOS 1969 block casting and it may not even be close to correct for a particular VIN. There's more of course.

Word to the wise, don't even bother re-stamping a ZL1 block.