Would this set up be desireable in my 66 Cuda?

id ask if it is a 340 or 318. probably a 318 for that price unless the guy is an idiot, really nice or doesnt know what a 340 is worth. 2nd ? would be why is he getting rid of it? not enough power? upping to a bb? i dont think id pay that much for a 318 unless it was REAL LOW mileage & ran real good