260-289/302?? Here’s how

I've seen alot of members that don't know if they have a 260 or 289 in their boat. The bell housings have different bolt patterns. So yesterday I measured my 260 and 302 bell housings. The two top bolts in the center of the bell housing on a 260 are 5 7/8" apart and the same bolts on the 302 are 5 3/16" apart. On the passenger side, the distance from the top bolt to the first bolt which is near the bottom of the head, is 5 1/4" on the 260 and 6 1/4" on the 302. So bolts a little closer together for more strength. Also another difference is just above the starter. On the 302, the last hole above the starter is threaded toward the bell housing and the same hole on the 260 is not which uses a bolt and nut. Now there are some early 289's with the 260 pattern made just before the new pattern. So the casting date will tell in those cases. The C on casting numbers stands for 1960's and the number following is for the year. an example would be C4 which would be 1964, and D is for 1970. I hope this helps.