How can i tell the difference between a 74ci. and a 80ci. Harley Davidson Shovelhead engine?

you need to know the year.- on the vin # if its got an A or E after the first number its a 1200 (74) if its a G or H its a 1340(80) after 1980 they changed their code but I think they were all 80s after that anyway. if youve got it apart check the stroke 74s have 3-31/32 stroke 80s have 4-1/4 they both have 3-1/2 bore the motor# should be stamped on the right front case its same as vin# if its got a generator its 1969 or older they were all 74s