Sold a clean but stuck ( wrist pins) 1973 YC 455 complete for 1000 this spring. 1500 buys a running one unless its a rarity. A 1978 455 would be a rarity been they stopped production in '76.
4-500 buys a rebuildable core 400 around here. Although I do see a downward trend as the LS based swaps become more popular.