I got one a few years ago that was running in a 72 Targa. We took a video of it running, not great, but it was running. I know a couple of the head studs weren't great and sold it needing work. Everyone told me it's worth $25,000. I put it out there for $20,000, it took almost a year to sell and it sold for $14,500.
So the real world price wasn't anywhere near what everyone thought it would be.
https://www.youtube.com/watch?v=Anc92Z3_WeU
---Adam