1969 340 water pump pulley

I would add, it isn't buying an incomplete engine that is the problem. Rather it searching for parts based on one only criteria. In this case "it is a 1969" , when in fact the engine is outfitted as a 1970 engine. The car it is going is has little bearing at that point. Understanding the differences between years and models, takes education, and sometimes that comes at the expense of buying incorrect parts, or impulsively buying something on 'assumptions' or the word of someone else who hasnt seen what you are building. Understand the whole mechanism and a desired outcome, one will be happy.
That being said, no one has mentioned that the radiator outlets will be the next mating issue to resolve. The alternator has already been forced into the discussion.
I won't belabor another point, I love correct engine color, a 340 in a 1968 would be red. Here, myself not knowing the engine origin, his choice of color may not have been given.

Red