Too cheap. Going price is more like $300. Understand, I clean them up (bead blast and repair all stripped threads) and no, I paid more than $80 for them. Then there is the carrying cost of money. I have been collecting parts for 45 years.
You can't buy a hemi cuda for $6000 can you? People complain about the high cost of late 60's and early 70's muscle cars, but look at the price of a Hellcat (or even a new Honda Civic)! When I bought that first LD340, I was making $2.20/hr! Lets put things in the proper perspective.
When we get older (I am 65) we think prices should never change from what we remember them. And yes, I bought gas for $.25/gallon when there were gas wars (who knows what a gas war was?)!