I recently purchased four 289 complete engines out of various cars from a local salvage yard for $200.00 a piece. Pretty much the going rate around here. No K Codes or anything like that but these engines are pretty plentiful. Remember that Ford produced over 600,000 Mustangs alone in l966 not to mention the vast number of other Fords that also used the 289s.
I remember, vividly, busting my hump doing service work for a leasing company that bought tons of full size '65-'67 Fords. I must have changed
oil and done tune ups on half of those 289 cars ever made. At least, unlike the Chev SB, the distributor was right in front of you. The big gripe was that Ford had the great idea of putting plugs instead of grease zerks in their front ends components. You had to R & R them everytime you lubed the front end. Sorry about the walk down memory lane.