Hi Bill, I only know that the 1969 to 1972 250's had straight up timing so that is the cam gear / timing set that I would use for a Performace build. You wouldn't want to use the other two timing sets used on the 1973 to 1980's 250 cam gear / timing set unless you were building a stock engine they all were 4 degrees retarded or more. Sometimes the pictures of parts on line don't match either today was looking up a 250 water pump and numorious places used a picture of a V8 water pump in their listings .