Depends on if it is (A) the "small" 3-tube version with cap in the center and a finger guard (standard on 67 396/325 cars), or
(B) the larger 3-tube version with cap on the driver's side and a finger guard (standard on 66 396/325 & 360 cars and 67 396/350 cars), or
(C) the larger 3-tube version with cap on the driver's side and no finger guard (HD on 66 and 67 396/325 cars with a fan shroud).
B is worth the most, C second, and A is worth the least.
If you have factory AC then it is presumably version C.
Then condition determines the value from there. If it is mint and has the original build sheet and part # ID tag still on it, and the core ID tag still on it, then it will be worth a whole lot more than if it needs work and/or is missing the tags.
Post some pics (including ID tags if still present), and folks on here can give you a better idea of the value.