67 z28 engine, or block

[Chevy454]

Same subject, different year...

What would a driveable early '70s Z be worth? Auto, interior not too bad, not sure if engine is original, looks like originally blue, and at first glance appears pretty solid. They've been driving it, but they swapped carbs (to a Q-jet!) using an adapter, it had anti-freeze puddled on the intake, and they said the brakes weren't working quite right. I talked to the guys wife and she said the orignal carb wouldn't work, so they swapped on the Q-jet, but with the adapter it makes it sit too tall, so they took off the air cleaner assembly! Needs LOTS of TLC, but it's not too bad for this area. Any tips what to look for, like trouble areas, or verification?