Parts for 1964 Interceptor 260

My parts manual shows 1000511 for the flywheel for a 1966 289 Interceptor. It also has another number for a Berley jet flywheel, so maybe they were Interceptor parts and not Ford? It has no other info. Here's a picture of the rear of the motor I posted above. I was told it was a 289 or a 302.

My measurement using a tape measure is that the spacing on mine is 5 13/16 inches, which is only 1/16 less than your value of 5 7/8 for the 260. It's definitely not close to the 5 3/16 you say is for the 302. So it's starting to look like it's a 260, right? Of course, I still don't have a spec for the correct flywheel, plate, or starter. It seems like any one of those three things being the wrong size could cause the starter to be too close to the ring gear and result in a chewed-up ring gear.