Slant 6 worth?

$500.
Only because you know the engine. To a stranger- it’s scrap price of $200.
Not counting the engine, except as a "core". When was the last time you tried to by a Offie intake with carb, or a A833SO with a Hurst shifter? If I were in that area I would jump all over that for $500 (with hurst shifter), and I'm a cheapskate.