what would a new 454 be worth

[68GMC454]

i got a lead on a suposedly brand new 454 for 600.00. suposedly the lady was asking 4000.00, now just wants it gone for 600.00
like i fell off the turnip truck yesterday..but hey you never know, could be a bad divorce, she also has a 66 buick regal i think it was for 2000.00
i will sell what ever i can get my hands on if she has paper work to prove its a new motor..hmm might actually get a 454 for my 68 after all,,